Looks to me like they've donated quite a bit of money to conservative democrats and republicans so I wouldn't exactly say they haven't entered politics.

https://www.opensecrets.org/pacs/pacgot.php?cycle=2018&cmte=...

Their CEO also sent a somewhat political all office email after the last presidential election: https://www.vox.com/2016/11/9/13576446/ebay-ceo-memo-us-elec...

My point is just to say that "market liberalism" is a stance, not the absence of a stance.