There has been a string of things, including Superfish.
There was also the Lenovo Solution Center problem. And the Lenovo BIOS shenanigans (or was it the Lenovo Service Engine?).
There have just been too many lapses in judgement at Lenovo. Either their competence is slipping or their ethics are. Either way, I'm done with them for now.
Although, in my opinion, I wouldn't trust any laptop hardware company out there enough to use the system that came pre-installed with it, but that's for another discussion.