It's easy to understand why Trump's base would be OK with Russian interference.

Because Russia helped to elect their boy. Otherwise, the Base would remain a political minority. Nobody taking them seriously. Their prejudices unaddressed. Their wish for their religious views to be enacted into law ignored. Democracy was passing them by every election.

So whatever it took to get them to the front of the line, they're down with it! Trump knows and appreciates that. Democracy is not how inadequate candidates get elected. Russians are cool (until their boy no longer matters to them).