Could you give me an in-game source on it- specifically, the part about the siege of Alinor being an ongoing thing? I'm aware of stuff like Warp in the West, but this is something different. Something that is tied in to the weirder- and grimmer- MK lore.
Yet blaming the TES III Empire onward for that is like blaming current America for slavery. And for what it's worth, they did a lot more for the Orcs than anyone else was doing.
Yet much of it were the exception, rather than the rule. People like Talos and Potema were never the norm for the Empire, especially not as of the events of the games. In the grand scheme of things, the Empire comes off as overall more benevolent than possibly any other rule I've seen going on Tamriel. The Thalmor, by contrast, do that sort of thing regularly, and continue to do so, without any of the Empire's redeeming features, and without any suggestion that the Thalmor's atrocities are not par for the course.
If we're going by the weird stuff, I must present this.
The Thalmor is easily the most dangerous organization in the Aurbis. Moreso than Talos.
-MK, Reddit https://www.reddit.com/r/teslore/comments/1ptr0o/i_am_michael_kirkbride_ask_me_anything/.
That said, he also said the Thalmor will ultimately win (no doubt referring to C0DA and Landfall stuff he presented later), and I admittedly would definitely be happier if Bethesda did not go down that path. In fact, I'd be pleasantly surprised if the Dominion evolved into something that I can't detest with every fiber of my being.
The Thalmor commit their atrocities more regularly, more consistently, and without any redeeming features to anyone who's not a purist Altmer. In addition, almost two centuries have passed and there's been no sign of them changing their ways or becoming more benevolent. Now, the Aldmeri Dominion as an institution might be redeemable as a faction, but not while the Thalmor are in charge.