this thread smacks of trolling, but i will assume you are serious and i shall play along.....

i dont know the situation, but i see no reason why a cyclist would ever or should ever ride in a way to block traffic. if they are on the edge of the lane, then they arn't blocking, if they are in the middle of the lane, they are, in my opinion, wrong.

i shall address your concerns in the order you listed.

1. so what if they are going slower? does that mean they shouldn't be riding a bicycle?
2. so what if they have a small helmet ? i dont' see your point. safety? just because you perceive their actions as unsafe doesn't make it so.
3. neon clothing doesn't make you smart, or safe. invalid arguemnt.
4. again...so?
5. sidewalks are for pedestirans, not bicycles.
6. perhaps because they find it fun. again, just because you dont think it's fun doesn't make it so.

i think mountain biking is stupid. i dont' understand why you would ride a bicycle off rocks, wearning only a little helmet. it doesn't seem practical, why would you do it? you aren't getting anywhere, you aren't doing it for any reason that is obvious, i just don't get it.

road biking is fun, maybe not to you, but to those who do it.

and why are you posting this in the mountain biking forum?