Good on you. I left Reddit when they locked Genzedong and i never looked back. It is such a breath of fresh air to be free of that toxic cesspit. It's not just the regular users who are awful, the mods are even worse, and the entire site is heavily controlled by three letter agency employes.
As to their "argument" against the SMO, it is totally moronic. Denazification is the best conceivable reason for starting a military operation. No sane country should tolerate a militarized Nazi regime on their border.
Also there's the little detail that the "WMDs" were a lie while the Nazification of Ukraine was so obvious even the western media were writing about it, and they are still forced to address it because every time they take a photo of Kiev regime soldiers - surprise, suprise! - there is some swastika, iron cross or SS badge that the western media need to twist themselves into knots to handwave away or justify.
And it's not just the Nazi problem and the NATO issue, far too many people omit what is probably THE main reason for why Russia HAD to intervene when they did, namely the eight year long war waged by the Kiev Nazis on the people of the Donbass.
However this, just like arguments about Nazis and NATO expansion, is pointless to bring up when talking to Redditors and will just fall on deaf ears because they do not view Russians and pro-Russian East Ukrainians as human, nor will they ever acknowledge that Russia has a right to have national security concerns and vital interests, let alone a right to act to address these when the West refuses to take them seriously.