Either Taiwan is getting pressured by China to not pull out their business or these companies simply do not care and prefer profit over bloodshed. The former is more acceptable but there have been other Taiwan companies that have pulled out of Russia, so why can't Lenovo and other mentioned companies?
https://www.crn.com/Lenovo-Acer-Asus-Get-F-Grade-For-Still-Operating-In-Russia-Yale-Report