Wow, newbie logic is great! Where did I say this post was in the wrong forum? I was just giving you advice because you seem to be too slow in separating riding type from bike type.

If you ride your mountain bike exclusively on the road, you're no different than all the people in the commuting forum (shockingly, many of them use mountain bikes!). You're free to post wherever you want but people in the commuter forums will be more inclined to answer questions specific to on-road riding (i.e., your fender question).