Who mentioned sidewalks?

Jonah, roadie commuters ride on the road because that's what they do. Unless you're able to claim them on your taxes, it's really not up to you if it's logical or commonsense to do so. I'm serious here.

If that's how they define themselves as cyclists, that's their choice. You want to ride the MUP in that area? Go for it -- if I lived where you do, we'd likely see each other on the MUP! I happen to agree with using that option -- for ME, it's the better choice. For them, it obviously isn't.

Pretty much, it's an extension of why we all ride; we're not taking the 'easy way' by pedaling wherever we go. They are not even taking the easy way available to the hard way practitioners!

Don't shake your head, or condemn them as fools -- cheer them on! They're livin' large! I'll use myself as an example -- there's not a damned thing in my area that requires a 6-inch-travel MTB! But that's my chosen commuter -- because I never know when I'll just give in to the impulse to hit the dirt, drop off something, just get funky. Once, I hit a short, steep rise in the ground that was half-washed-out by rain, the top of which was a narrow gap in an 8-inch-high curb in an apartment complex parking lot, just off the MUP. I hit the rise wrong, and missed the gap, without a chance to pull up the front wheel. BUMP! Right over it, barely felt the thing. My hardtail would have faceplanted me on the curb itself.

Live and let live, dude.