They are not doing anything illegal, and are not harassing or threatening anyone so nothing wrong.They are simply enjoying their time in a warmer climate on the beach which is rare in Russia.
That's not true, public nudity is illegal in India. It shouldn't be, but it is.
You are right. We should all be walking naked on the streets.
I am sure you would have trained your daughter to walk around naked in public just to prove you are not a uptight Victorian prude.
If everybody walked naked, but did not harass each other, it would still be a better society than the one we have currently, with rapes and sexual assaults and harassment everywhere.