You'd be more accurate in saying that Law is easy than uncompetitive.
It received the most applications of any course in the UK for 2005 entry; and a large proportion of those applications came from straight-A students. However, Law is a degree also offered by a number of lack-lustre institutions, in which case it is fair to say that an applicant to such institutions is unlikely to face much competition; but that applies to all subjects generally.
In comparison to most degrees, Law is extremely competitive.