Dismissing people's real concerns is how you get them to vote for parties you don't like. Fact is that the new caps do make it easier to end up without a good seal.

That's only a "real concern" if... I don't know, if you're somehow exceptionally clumsy? But then, you'd be much more likely to drop the old-style cap while trying to screw it on, so the new one would probably be an improvement. So no, it is not a "fact" that the new caps make it easier to end up with a bad seal. I rather think you'd have to go out of your way to specifically do that.