Yes and no. Technically yes... in that it owns both companies, but no in that it is under Activision in the company structure as a publisher developer relationship.
It's like Netherrealm Studios is owned by Warner Brothers, but through WB Games.
EDIT: I'll admit that Red Alert 3 went full camp, but I don't buy the story gripe (since time travel plots are inherently screwy by their nature), and I find it mercilessly ironic that you're calling out Jenny McCarthy on being a Bad Tanya when the most famous of them is best known outside of gaming for her Sexploitation films, also, she's not that great either. I mean it's all subjective really, but I think it's just funny.
I think they went too camp - RA1 was a pretty generic war story, but RA2 was the pinnacle of the series. It struck a balance between goofy and entertaining, and then - rather than have any actual, you know, story advancement, they got lazy and mashed the reset button again, replacing Prism technology and nuclear weapons with...shrinking freeze rays?
RA2 had great actors for both factions, even if the budget for all the scenery they chewed was immense - Einstein, Romanov, Carville, Yuri, President Dugan, even Gen. Vladimir. With the new cast, the only character I can even remember the name of who isn't a franchise staple like Eva and Tanya is Pres. Ackerman - though I'll say the Lt. Eva actor was an improvement, and only because of the stupid subplot with weaponizing Mt. Rushmore and him being a Japanese robot clone in the Rising Sun story arc.
as for McCarthy...maybe it's just that don't like blondes, but I considered Kari Wuhrer to be both hotter and a better actress. Tanya's supposed to be hot, rude, and tough - McCarthy got the first one down fine, but didn't pull off the second and third nearly as well as Wuhrer did.