I wanted to point out to you that there are other reasons for people choosing different choices to you which don't involve them being "tired of learning" and "not being very good".

You described yourself as being "used to keeping several languages in [your] head" as if this was an achievement that others couldn't muster.

I still feel that your derision towards others and self-congratulatory tone were deserving of rudeness and snark.

Anyway, I apologise for being rude since it was hurtful. I thought your comment was bad and let you know this by directly accusing you of exactly what you were doing, instead of finding some non-confrontational way of saying it.