The Senseless Sacrifice page's title does nothing to differentiate it from the very different Stupid Sacrifice. Various suggestions like "Vain Sacrifice" or "Downer Sacrifice" are offered in the discussion page.
Looking through the examples, there does seem to be some misuse for Stupid Sacrifice.
In the characters ending, Xianghua of Soul Calibur does this in the fourth game, senselessly holding on to Kilik as he sacrifices himself to neutralize both Soul Edge and Soul Calibur. He was going to die, with nothing that could have been done without another characters interference, and there was no reason beyond suicidal devotion for Xianghua to go as well. What a senseless waste of human life...
MS Saga, a Gundam spinoff RPG, has Gavanger make a Senseless Sacrifice fairly early in the game by trying to hold off the Psyco Gundam on his own while the rest of the party escapes. The "senseless" part comes in when you realize that even the best MS you have available at the time wouldn't have been much more than a speed bump to Psyco Gundam. The situation is deliberately Gundam-Troperiffic, paying homage to the franchise's long and glorious history of similar sacrifices.
If people are misinterpreting the title, and confusing it with another similar trope, I think it's a good idea to rename.
I think it would be better to use idiom in vain rather than just vain (Sacrifice In Vain rather than Vain Sacrifice), as that makes it clear which definition of the word is used. Doing it for any prideful reason implies there may be another choice, in which case it falls under Stupid Sacrifice.
Useless Sacrifice would also work.
I agree that Vain Sacrifice or Sacrifice In Vain is probably the most idiomatically correct name. (I think Senseless Sacrifice is probably also a common idiom, but I agree that it's ambiguous, and since we have another common idiom we can use instead, I think it's worth switching.)