Even if those societal effects were true (there are studies for both sides, and especially the helmet opponents are usually very outspoken and even rude, to the point that they lose credibility), the important thing for me as an individual is not whether helmets lead other people ("the society") to cycle less, but what the effect is on me.

Personally I feel some chilling effect (sometimes I cycle without helmet, so some friction is certainly there). But it's not very strong.

On the other hand, I have never consciously experienced a difference in car driver's behaviour whether I wear a helmet or not.

And I certainly am not cycling in any riskier way when I'm wearing my helmet. If you do, you should really think about what you're doing.