I won't say that men should never
dress colourfully, but I would advise caution because surprisingly few men actually pull it off.
Colours look their best when the saturation isn't too
high, when the fabric is of a good quality and weave, and when paired with colours that aren't as harsh on the eye. Those red pants look cheap and tacky. The colour is very bright and I would not be wanting to see them accompanied by conservative stuff.
The contrasts in the outfit you posted are not easy on the eyes. Black and blue go together but it's a conservative pairing and, since they are both on top, that pairing only served to throw into sharp relief the stark contrast between the business-casual style of top half and the ... clown-casual bottom half. The components didn't blend at all.
I know you want to wear something other than denim, but there's nothing charmingly quirky about bright red pants in such an ensemble, it just looks stupid. If you want to wear slacks, there is no reason to jump into extremely bright colours; opt for earth tones and neutrals if you dress conservatively or, if you want to start dressing colourfully, think about altering the other parts of your outfit accordingly.
Here are two denim-free outfits in your blazer-shirt-slacks configuration, but with better colour combinations. One with
those ghastly red pants, one without [but with a ghastly shirt instead]
Personally, I don't like cream coloured pants and I saw them everywhere last year, but the grey pants on the H&M website looked... weird. It all looks weird.