Whatever the reason for their policy, it provides a nice sense of safety to Linux gamers. They can buy the game without worrying about compatibility; if the game doesn't run then its two clicks for an automated refund.
Sure, but I imagine they saw the dominoes falling and realized that the optics of going down kicking and screaming in endless battles against basic consumer rights would be exceptionally bad. If they hadn't fully conceded then the EU would have been up their ass too before long.
AFAIK Steam has this too. The Subscriber Agreement clearly states that you're not guaranteed continued, free access to Steam. If they decided they wanted to charge you to access games you already bought, they could.
They only begrudgingly conceded refunds in 2015 after the no-refunds policy they had maintained for 12 years was found to be illegal in Australia.