is it really a tank meta?

Meh. Kind of, but for no real reason.

The Jungle item made tanky jungle more effecive overall. But Tanks have popped up in all other lanes to varying degrees for no reason at all.

The community is sheep. A segment of people made it a huge talking point about "tank meta" because of the item, so people sarted picking tanks again even though nothing but a jungle item changed. There was a ton of talk about smite top's but I dont even see it that often, pretty rare.

And its not as oppressive as the true tank meta was. Tanks are tanky, but Half the time I see them lose just as hard as anyone else.

Its just a buzzword.

I see assassins deleting squishies, ap nukers nuking squishies, I don't see what the problem is.

And everytime I see a tank kill someone, it's with their team. Never seen a tank 100-0 anyone unless they're extremely fed after a few ganks.

It's not all about tanks, but their (now noticeable) presence changes how the game is played from what it was before, and it's a fairly large difference.

Before, you had maybe an initiator (or at least someone tanky) pretty much ring a bell, then you'd have a brief mini team deathmatch. That was teamfights, you may have had tanks appear every now and then, but generally whoever had more burst would come out victorious unless a tank had a good amount of money on them or the support was good enough to peel the sudden barrage of fun.

Now you have a tank, and these tanks do their jobs well, quick enough. The clear speed (and bonus HP) buff for tanks in the jungle made it reasonable to pick them. They appear earlier, get tankier earlier, and become a wall earlier. The reason it's the called the tank meta is most likely before the Cinderhulk patch it was just a fun little kill spree, but unless the tank is ahead of you they aren't going to kill you outright.

So no, I don't really think labeling it the 'tank meta' is completely correct, it's more like the "Playing the game right" meta.

Not sure why it's a "tank meta", the most popular jungler is still Lee Sin, Vi is still top 3 as well. Top lane Riven is #1, then Vlad, and Nasus. Supports being tanks have been a thing for a while since Leo, Thresh, and Blitz were most popular for ages. Then mid still has assassins and mages being picked, and well adcs are still required. Tanks are simply finally being picked sometimes outside of support for once.

Just played a game as malphite, had the most damage dealt to champions in the game. I was full tank. Does this answer your question?

imo its not a thing they have become relevant in the jungle due to cinderhulk and i think the other jungle items could be brought up power wise to compete a little better, but literally nothing else for tanks that effects them all as a class has really changed