Eugene gets accused of block downvoting, based on the incontrovertible evidence of multiple posters not being terribly fond of him.

This is not at all a reasonable summary of what was going on there. A specific reason for focusing on Eugine was given, and Eugine's continued lack of comment at this point is not helping matters. (That's unfortunate because I'd much rather believer that he isn't doing this.)

You judge that he is not only guilty of block downvoting, but specifically targeting feminists because of his reactionary politics.

Not necessarily feminists per se, but the fact is that almost all the people who have experienced mass downvoting are people who have argued against traditional sex or gender roles.

shminux has been block downvoted, and once made a reply to a comment espousing a neoreactionary view of gender.

Shminux made a (somewhat insulting, not necessarily productive) comment, and the downvoting experience started off shortly thereafter.

view of gender. Therefore, as the author of said comment, the implication is that I must have waited for "a few days" and then systematically downvoted all (or just most?) of shminux's comments. Because the comment did something to "aggregate" (aggravate?) me or maybe just out of solidarity with other reactionaries (because I guess that's what we do now?).

Adele_L said nothing at all about you being involved in any way with any block downvoting behavior.

And the idea of using mass downvoting to harass people I dislike is the kind of passive-aggressive thought policing nonsense which made me stop being a progressive in the first place (seriously, using anonymous voting to shut someone up by making them seem unpopular... how is that supposed to be right wing?).

Let me tentatively suggest that there's nothing intrinsically "right-wing" or "left-wing" about such behavior. It may be manifesting itself in a specific political framework, but very likely is more a function of the individual or individuals engaging in the behavior than saying much about their political alignment.

But politically motivated mud-slinging and invocation of the mods to remove people you disagree with is absolutely beyond the pale.

The primary invoking of the mods I've seen here has been to actually take a look and see who the downvotes are coming from. That's a pretty distinct situation.