Algernon is comic because he is witty and subversive?

Throughout the play Algernon subverts social norms, while concealing his subversion by adhering to social convention (which is the definition of Bunburying). When he says "if the lower orders don't set us a good example, what on earth is the use of them" he is subverting the Victorian ideal that the upper classes should set good examples to the lower, in terms of charity, manners and decorum. It also reflects Algernon's defiance of social convention by attaching value to the behaviour of a member of the serving classes. This is also an example of irony. Other examples of this:
"The amount of women who flirt with their own husbands is perfectly scandalous" projecting the idea that women should flirt with men other than their husbands is a direct attack on marriage, coupled with "is marriage so demoralizing as that?". This is another attack on a stable convention of Victorian society and may also reflect some of Wilde's own beliefs on marriage. He further develops the idea by parodying the cliché "washing one's dirty linen in public" into "simply washing one's clean linen in public" By switching "dirty" for "clean" Wilde creates a metaphor that says exactly the opposite of its original intention, but is instantly recognisable. This is also an example of his whit.
Algernon's response to Aunt Augusta when she asks "I hope you're behaving well - Algernon - "I'm feeling very well" showing his whit and desire to mislead his aunt. This one being so blatant that she catches on quickly.
"My dear boy I love hearing my relations abused" - Again an attack on the Victorian values of family (subversive).
One of my personal favourites of Algernon's whit is when Jack says he's "sick to death of cleverness" and wishes there were "a few fools left" after Algernon says "we have" Jack wants to know "What do they talk about? - Algernon - "The fools? Oh! About the clever people of course". Here Algernon has set a double trap for Jack indicating that Jack is a fool for discussing clever people and the Algernon is clever for not talking about either. It is this kind of syntactical baiting and trapping that characterises most of their arguments.
However for all of Algernon's whit and sarcasm and subversion all of the action in the play takes place in very conventional social settings and Wilde's choice of using the upper classes for his main characters gives him licence to use language of a higher register than would have typically been seen in melodramas of the day (usually focused around middle/lower classes and containing more elements of slapstick and lower humour).Algernon's participation in such mundane a social activity as receiving his aunt for a lunch of "cucumber sandwiches" is a direct subversion of his own personality and could be construed as hypocrisy. I feel that this is an important point also in that by setting the action in typical social circumstances (a tea party, a proposal, lessons in the morning, scrutiny of credentials leading a marriage etc..) Wilde gives Algernon and other characters (Jack particularly and Miss Prism and Dr Chauble's various benign activities leading up to indiscretion) the relevant social conventions to subvert. In a way he engineers the very conventions his characters mock.
There are many more examples of Algernon subverting conventions, but I think the best way to discuss his whit is in his arguments with Jack. Algernon and Jack present two equally similar and different people. Jack is using his "bunburying" to try and win the heart of the woman he loves; where as Algernon is using it for kicks in the country. They are so dissimilar in their desires that they are exactly the same in many of their actions. Even repeating dialogue and many of the plot points in TIOBE. The way Wilde uses dialogue in TIOBE represents stichomythia (a complete line of verse being split over two characters) "Jack - "That, my dear young friend, is the theory that the corrupt French drama has been propounding for the last fifty years." Algernon - "Yes; and that the happy English home has proved in half the time.". By splitting jokes like this between the two characters Wilde shows his own subversive thoughts through the responses of Algernon and indeed Algernon frequently subverts Jack's own ideas through his responses. Other examples included:
"Jack - "Your duty as a gentleman calls you back." Algernon - "My duty as a gentleman has never interfered with my pleasures in the smallest degree" Also being an example of an isocolon (parallelism) where Wilde uses the same syntactical structure "duty as a gentleman" to subvert the idea of how a gentleman should behave, indicating Algernon views gentlemanly conduct as something employed for pleasure rather than manners.
"Jack - "You have been christened already." Algernon - "Yes, but I haven't been christened for years" - Subverting the idea of christenings as a religious ceremony by engaging with it to further his romantic desires. This also shows Algernon's refusal to accept Jack's point is ever valid and further reflects his argumentative nature.
There are many more examples of stichomythia in Jack and Algernon's dialogue that all pretty much shows how subversive Algernon is.
Finally there is some display of subversion and whit in how Algernon speaks to Cecily. "Algernon - This world is good enough for me, Cousin Cecily." Cecily - "Yes, but are you good enough for it?" This reversal of Algernon's dialogue being subverted by Cecily may be an indication of how alike they are. It also shows how Algernon's use of whit changes when dealing with a love interest rather than Jack.

That's it. Hope it helps. If you disagree with anything I've said or think I've missed anything out add it in I'd love to discuss other people's thoughts about this (as indicated in my other thread )

Thanks

Mr.P