The problem is that you don't want to be the kid who cried wolf, you don't want to be endorsing crying wolf, and you in fact maybe even want to punish the newspapers who cried wolf and said you were responsible for the cry.
SETI wants to have the ability to say later, "guys, we have a signal, and this time we think it's real." The best way to have that credibility is if your members are the most likely to say "hey, I know the media is really interested in this but we're really hard-nosed skeptical bastards who aren't going to fool you, this is probably nothing." Then when those people actually say "this is probably something!" you're like, "woah, even the hard-nosed skeptical bastards are throwing in with it."
Depending on your perspective this is either undermined or enforced by the way climate change has been approached. Climate change has been an indisputable fact compelling so many hard-nosed skeptical climate scientists for so long, that now the deniers no longer believe that the scientists are hard-nosed or skeptical. So maybe this is misguided and "haters gonna hate" anyway. But I can understand why it's the default attitude in a tenuous field like fusion research or SETI.