People wanted to keep him because to a shrewd fan who wants to win/wants the best outcome, the devil you know is more comfortable than the one you don't. Especially when news of Jenkins/1st round talent you traded up for in the early 2nd needing surgery hit.
A lot of idiots on this site wanted him to stick around, maybe not as a longterm answer but both his salary and level of play were unacceptable. The market showed (at 4.5 mil he got from Washington/near 1/3 of what the bears would have been paying him) that he sucks.
The narrative was "we don't have Jenkins so I want Leno back." It was dumb then. Its dumb now. You're a shitty contrarian to downplay that otherwise.