I mean, you are also spinning it. People already had that alternative, everyone's free to levelup whatever characters they want without the buff.
Blizzard doing a capitalist move to profit from people being quarantined and improve revenue is not that surprising, and to be fair not that wrong either (in this particular way at least).
The buff definitely is supposed to entice people to play, not just out of the goodness of their corporate hearts and to enjoy seeing people leveling up. On a corporate level Blizzard doesn't give a damn whether you're busy with leveling, endgame content, erp-ing in Goldshire Inn or just afking in town, as long as you're paying that subscription (and maybe ocasionally dropping some extra money on store items).
The wrong part is alleging they are doing it because WoW is doing bad, and not simply to increase profit (ie: They'd still have promotions like this even if they had 20M subscribers, because what's a lot of money when you can have all the money). Also because recently they need all the good PR they can get.
- - - Updated - - -
Take from that what you will.
I would think it is almost exclusively related to the progression of Covid-19 and more people getting quarantined every day, rather than a 100% exp boost in WoW. But that's just as post hoc, to be fair.