Again I underline that monotheism is the biggest threat for Slavic people, Slavic heritage, and Slavic believs.

Sorry but you are wrong.

For centuries my ancestors were christians and they also observed many pre-christian traditions. Then came Yugoslavia and in this period they mocked and destroyed these traditions. Thanks to evil anti-slavic priests many pre-christian tradition's have been revived after Yugoslavia collapsed.

Taking many pre-christian traditions in the Christianity is only a insult for the Slavic heritage, in my opinion. From the other hand, its good because it still survived, thats true, but it exists now in christian surrounding and meaning, changed and merged like it is authentical christian. And its celebrated not by our own originall rituals dedicated for the native gods, but for Christian saints, with Christian rituals. So, it has not any sence for me. Plus – none of random christians will ever think and understand that those traditions have nothing to do with christianity.
For example, many random Bosniaks (muslims) too don't understand that Jurjevo, or Perundan (Ilindan) is their own holiday and that such a celebration is a native tradition. For them, its just a christian celebration, and they don't want to have anything with it.
But, thanks to the gods, some of them know the truth, and in some willages, Bosniak muslims still celebrate it, but, in some kind of "islamic tradition", that is, the same as in "christian tradition" a insult for the originally slavic heritage.

Dude pre-christian traditions are mixed with christian, muslim, etc. traditions so much that they are Christian etc. traditions now. We dont realy know much about how paganism exactly looked and worked like back then (especialy Slavic) except for leftovers in Christianity and Islam and some old books which mention it, but thats about it.

Modern neo-paganism is more or less bunch of atheist folk having a good time in the woods and few hardcore neo-pagans trying to revive it in a neo-hippe, quasi-green way.

And because Christians take those traditions (dates and concept) it looks like those traditions are Christian. If somone would try to revive it, he will do it on the way christians do now, not on the way it was celebrated.
And how can we know it?
1. Christians burried all pagan scripts, books etc.,
2. Christians moderate all pagan believs on their own.

And its not a problem for you for the Slavic heritage?

PS. Just not to be confused, I admint and agree that monotheistic religions saved those traditions from being forgoten, but they contaminated them with their believs, rituals and traditions, so we can't know now what was really original.
I mean, we can still find some informations about that, and reconstuct it, like ethnologists do, but its quite hard because every holiday is conected with a Christian holiday, tradition and ritual…