What sums the guy up for me is that he voted to have his wife thrown out of the party, and endorsed the slander campaign against her, that she was a Gestapo agent (which she plainly wasn't). The fact that she was his wife adds piquancy to the tale, but it is not what is so destructive. It is Althusser's support for the reactionary political movement called the PCF that really damns him.
Maybe you disagree? But the truth is that the official Communist Parties were vicious counter-revolutionaries who fought to suppress working class militants all across Europe. His tawdry theoretical gee-gaws are not important, except for the fact that for a few years, his obscurantist books tempted a few people to hope that the PCF might be home to a more positive development.
But there it is, he never left the party (except when asked to on the grounds that he personally had become an embarrassment, i.e. to save the party). Why did he kill Helene? Because she said to him over and over again (I won't say 'nagged', but she was, according to him, insistent), she said: 'leave the party! Join the revolution. Your ex-students are out there fighting in the streets. But you still support the party that is denouncing them as trouble-makers.' (not verbaitm, but pretty close, see The Future Lasts a Long Time). That is not a case of being personally bad: Althusser was a public figure. He made a choice. He chose reaction over revolution.
The people he allied himself were vicious thugs. Like all the official Communist Parties, the PCF sanctioned the use of lies, slanders, violence, shopping opponents to the police, shopping opponents to their employers, and political assassination - and to what end? The end of preventing social revolution.
What was Helene Rytmann first hounded out of the PCF for? Because she was a militant of the resistance, who did not accept the party line post war, that the social revolution had to be stopped, and French capitalism restored to power.
I remember full well what the PCF that Althusser supported was like. One of its provincial Mayors led a mob with a bulldozer to knock down a migrant hostel. It opposed Algerian independence.
The Communist Parties of Europe were steeped in blood. They assassinated Seamus Costello and Miriam Daly. They murdered many of the Castoriadis' Greek comrades. They clubbed and punched the militants of the Liaison Committee for the Defence of Trade Unions to the ground. They called the British secret services in to deal with the Tyneside Apprentices strike. They had Bob Shaw blacklisted. They refused to support Des Warren the jailed Shrewesbury picket, leaving him to die of Parkinson's disease brought on by his imprisonment. They had their own Edith Bone imprisoned in Hungary for years, because she criticised the regime there.
If you were in this gang, you were a force for reaction in the world. Giving the PCF a little bit of left-cover, just at the point that militants were beginning to see through its crap, that was Althusser's greatest crime. His conjuring tricks with the 'parallelogram of forces' are of minor academic interest - to the extent that they are in theory what his counter-revolutionary politics were in practice, the suppression of human agency to an inhuman bureaucracy. I would piss on his grave, but he beat me to it, making himself in the end the laughing stock that he ought to have been from the outset.