It isn’t a slap lawsuit, it’s an lawsuit to prevent the trademark from being lost. You have to defend trademarks or you lose them. Chances are the suit is filed by their trademark lawyers or even third party, and no higher up at Lenovo had anything to do with it.

I doubt their trademark is for the broken o though because that’s far too common. It’s more probable it is for the whole word including the stylized o. So the suit is pretty weak and only works because this is an opponent that probably isn’t going to be able to mount a defense.