I still am failing to see any real reason why there being Nazis in Ukraine is such a big threat to Russia. It's not exactly like Russia is 100% kosher and doesn't have any Nazis. It's like the incubators in Kuwait only more retarded as an rationale to invade a country.
It is not the existence of Nazis themself that is troubling for Russia, it is what typo of Nazi they are.
While Russia have it's own cooky characters, such as NazBols and Slavic Nazis(though in a past decade there were severe crackdowns on both right extreme (skinheads, Nazis of any kind, open Ultranationalists and other assorted extreme right wing ideologies) and left extreme (mostly Antifa)), non of them sees Ukrainians as anything but Russians and feel that split was a mistake(if not outright Western sabotage or Jewish plot).
In case of Azov, Aidar and other extreme militants, they wish nothing more then decouple themself from Russia at any cost at best and eradicate Russia as a concept all together at worst.
And based on those goals you can understand why almost anybody in Russia would hate them. Common Russian boomer hates them because they are claiming to be Nazis, and Nazi killed his father or grand father in Great Patriotic War. Russian styled Nazi/right wing radical hates them simply because they are splitters and overall Jewish puppets. Communists and Socialists hate them, because they are nothing more then unfinished Nazi collaborators with which USSR fought into the 50s and the remnants of them were took under CIA wing. For Russian liberal they are simply too intolerant and brutal to leave them walking as free man. Panslavinists hate them because they force new identity that, in there mind, should not exist. And, of course, for Russian Government this is organization in which every scorned radical who is upset about Russian system or Russia itself can go and be a pain in the ass.
For most Russians Azov and their ilk simply must go and never come back.