ronn1 is probably referring to a certain hoax/story underway right now. It's a good place to go if you want the thread locked.
Bigfoot confirmed will hurt a lot of people who took positions without properly assessing the evidence. "Scientists" who were wrong and staked their reputations on it, newspeople that laughed about it and anyone else who said they thought it was a joke. Supposedly, 70% of people do not believe it is real. Humans in general, have a lot of vanity, insecurity and arrogance. Being wrong is socially discouraged... to the extent that even skeptically investigating bigfoots is deemed kooky. Social pressure put us here.
I suppose there are also others who see financial difficulty if more greenbelts are designated where they want to log or develop land. I have read that logging companies know the truth and hide it. If there is a sighting they may do a weak hoax to discredit the real event. I've joked a few times that for every real ufo sighting, the CIA does nine hoaxes. Then they can say "90% chance it's a hoax" and leaving the remaining 10% to be kooks and misidentifications, lies or anything else that probably isn't the real thing.
As far as the government goes... they have a reputation for protecting us and knowing enough about the world to be able to do that. They haven't told us much about bigfoots (or ufos), so the assumption is that they don't exist, or else we would have been told about them. The notions that our government doesn't know, or has lied about it and withheld the information, undermines their credibility in a big way. The "status quo", is important enough for some people to protect it at all costs. The uncertainty of what would happen if that is disrupted is just not worth the risk. Mitt Romney joked about bigfoot being a hoax... He'll look even dumber if it isn't. If bigfoots are real, then what other conspiracies might be true?... ufo's, 9/11, WMD's... North Korea? Iran? My congressman, the Senate. Why should I trust anybody? or pay my taxes? A major credibility crisis... hypothetically. This is why no one with a real body could even talk about it and ever expect to show it in public. It simply can't be allowed to happen.