This is a really low risk signing with a chance of some reward if the guy can stay healthy. Maybe he can't, but for a team in rebuild mode this is a great flyer. If nothing else the Jets added a young WR with NFL game experience and upside. I'm not sure why people are complaining about it. Its not like he signed a guaranteed contract with lots of cash. C'mon guys, stop being dark siders for awhile and try to embrace the rebuild.
There's absolutely nothing wrong with this signing. The guy has size and speed. He's flashed a bit but has been injured a lot. There is no reason to be mad at this. There is zero risk. If he doesn't pan out who cares. If he does, that's great.
not to also mention, in much of his tenure with Chicago he was behind Marshall and Alshon, survived coaching changes, the drafting of Kevin White, the ludacris signing of Eddie Royal, etc. When he has been given true opportunities he has had nice games. He had a nice game last year where he got a decent amount of targets and went off for over 100 yards and a touch, with Matt Barkley.