I've 3 ThinkPads and never really dealt with Lenovo.

The reason why Linux users love ThinkPads is because they're mostly supported OOB by the kernel (not by Lenovo themselves). This wasn't true of most other laptops for quite a few years.

I bought my T61 in 2008, and the ThinkPad recommendation was old then. Things change with time. I believe most laptops these days are rather standardized, so linux support is ubiquitous.

My point being, it's not really Lenovo supporting Linux but the linux kernel drivers that for a number of years supported ThinkPad OOB where all(?) other brands required a lot of fiddling.

(And you probably just need to install thinkfan if you have full speed fans. Check out the ThinkWiki for your models.)