Are VFR pilots required to avoid an isolated cumulus cloud like any other cloud?
I suppose the FAA could violate you if you approach a cotton ball, but other than that, is there any reason to deviate and go slaloming around the sky just to keep distance from FEW clouds?


Aside from the legal reasons, keeping a healthy distance away from clouds is a Good Thing because other aircraft, birds, or alien spacecraft may pop out of them. Mid-Air collisions are no fun for anyone.

As far as going "slaloming around the sky", there's generally no reason to do that to avoid clouds:
If you're respecting the cloud clearance requirements (or at least the intent behind them) you shouldn't be getting close enough to clouds that you have to aggressively maneuver to avoid them - you've got plenty of distance to decide what you want to do.  

Remember too that you've got 3 dimensions to work with: If we're only talking about a "puffy cotton-ball" or two you can always climb above or descend below them and stay on-course, or if they're all lined up inconveniently right along your flight path just offset your track a little bit (no reason to keep zig-zagging if a mile left or right of course keeps you clear).