It is against the law KT - whether you agree with it or not, it is against the law.
To be honest though, I judge each case on the situation.
If for example it was a child, or someone riding fairly slowly - giving due regard to pedestrians, then it doesn't bother me at all.
I accept that the roads can be daunting for some folk, and are definitely not the best place for the timid, or for youngsters.
However, when I see teenage (or even adult) idiots flying down pavements, with no regard whatsoever for other legitimate pavement users, it really makes my blood boil.
My bikes are out and out road bikes, and I use them solely on the roads.
I would say that I am a confident cyclist. I know my rights, and by my actions whilst riding, I demand that other road users acknowledge my presence, and give me space to legitimately go about my cycling.
I always wear high visibility cycling jacket or shirt, and would never think of cycling without a helmet.
Yes - uncool it may be, but I got thrown over the bonnet of a car four years ago, by an idiot reversing out in front of me. Luckily I only had cuts and grazes, (along with £800 damage to my bike), but my helmet was severely damaged when my head hit the ground. - Much better to have a broken helmet than a broken head

).
Even after that, and a couple less major mishaps, I'm still a great believer in the benefits of cycling. But some of the people who ride bikes just don't have a clue. (Well they do, but they choose to go by the "I'll do whatever I want" attitude, regardless of laws/regulations, which gets cyclists in general a bad name).
Regards,
Mike.