I mean, one was viewed as being supportive of an ongoing terrorist campaign, a touchy subject in both Ireland and the UK, that no TV channel wanted to get involved with, and the other was viewed as a dumb cringe-inducing stereotype.
Imagine the tables were turned and an Irish or British show airing in 2001 had an episode where they appear to be supportive of al-qaeda carrying out 9/11, and another episode where they depict Americans as being fat, uneducated, pickup-driving hillbillies with tacky bleached blonde hair.
I suspect US networks wouldn’t show the first episode, but they’d show the other one, even knowing it’d elicit an eye roll and a “Christ, is that really what they think we’re like?” from the audience.
I get why they banned the one they banned (even though I wouldn’t have been okay with it at the time), I just think it’s funny because Up the Long Ladder is basically “let’s cram as many Irish stereotypes into one episode as we possibly can” and they didn’t think that it might be extremely offensive to Irish people.
EDIT: Just the very concept that Irish people would colonize another planet in order to be pig farmers is pretty offensive.