This isn't religious freedom. This is typical Russian xenophobia. Also, the idea that mosques cannot be freely built with private money is silly at best and tyrannical at worst. I can't speak to the fears of the Russian people, but I'm sure it's similar to the fears of most European countries currently about Muslim migration. They should show tolerance since there is none in the Middle East. However, they should make sure the rule of law cannot be handed over to the possible theocrats they're guarding against, which is sensible. The mayor of Moscow comes off as a thug, but go figure. lol.
I'll add- he is absolutely right to deport any illegals, which he is doing quite well based on statistics alone.