Academics
I'm not any sort of expert on anti-spam measures, but I do know something about academics:
It all depends on which academics were involved. If the university department involved has just been through some radical cuts (and I believe the Baltic states have been very badly hit by the current financial crisis) it's quite possible that the only person who really understood how the thing worked had just been made redundant by those in charge, who really hadn't the slightest idea what the department was doing.
And/or the whole thing was passed on to the newest member of staff, who said they understood it, but didn't.
And/or running this department was a job for 20 working staff and there were only 3 of them - they ignored emails because they needed to sleep.
And/or there's a "who cares anyway?" culture in that department/university/country. "Oh, I never bother with abuse emails - they're more trouble than they're worth and usually just banging on about something we all have to put up with. Golf anyone?"
And/or there's at least one abusive spammer actually in the department/institution who's cleverer than the people who supposedly run the operation, and they just re-direct the email into the "junk" box. Crime pays a lot better than universities.
And/or no one in Latvia sees why this sort of thing merits that sort of response - they may regard spam busting as "Just these Health & Safety Nazis trying to ruin things for small countries in a difficult world."
There's probably a Latvian equivalent of the Daily Mail claiming on the front page that. "EU bureaucrats are trying to block Latvian free access to the Internet" (and yes, I know Spamhaus is not only non-EU, but not an official body of any kind." - and they may know, but why waste good propaganda?) and inside that some poor businessman is overwhelmed by spam and someone should do something about it. Meanwhile they have a centre spread about how Latvian taxpayers are supporting idle academics just to keep some unnecessary geek fiefdom going, and to impose a lot of fancy rules on "the rest of us."
I do not claim that any of these things is actually happening - I have no knowledge of the workings of this ISP in particular or of Latvia in general. But human nature, and the behaviour of human organisations - especially in times of stress - is rather easier to generalise about.