While some fans may be bi-polar, if you'll look closely, many of the negative nellies are posters who rarely have posted and are coming out of the woodwork (like roaches). You don't see anyone who has been level headed or optimistic, suddenly flipping. It's just guys who have been negative all along, but remained quiet waiting for their chance to scream SOJ and the CS and team sucks, etc. It's disgusting to read that crap, but I feel sorry for them. They are miserable human beings obviously.
It shouldn't worry you. They initially had Geno over Fitz because Fitz was coming off a major injury, had taken almost no snaps, and because they needed to see if Geno could develop into their QB of the future.
The Jets do seem to have a knack for attracting miserable human beings..... Well, that or the Jets have a knack for turning normal, rational people into extremely miserable ones. Either way...