As I've mentioned elsewhere, Free Basics isn't the only offering that solves the problem. There are other options, and other models which have worked which Free Basics could adopt instead.

From that point of view, there are things which are strictly better than free basics which address these concerns (and net neutrality affects everyone, it's not just the "choice" of the people using Free Basics).

If these other models didn't exist there would probably be a weaker opposition to Free Basics. I'd mostly be on the fence -- preferring that net neutrality wasn't affected, but still supporting (or, not opposing) Free Basics since it's an IMO net gain. But these other options do exist.

What if there was a way to get the stress relief and other effects of smoking in a perfectly healthy and otherwise equivalent way? Would you ban cigarette smoking then? This "safe smoke" is not inferior to regular smoking according to smokers. It feels the exact same and has the exact same effect. If this exists, why allow cigarettes to exist? Okay, maybe you still want that choice. What if secondhand smoke was a much larger danger than it is now, and if a sizeable chunk of people start smoking, a lot of other people may get cancer just by sharing the same streets? In that case, would you allow it?

It's the same situation here.