Because you are ahead of a LAG's opening range, but are OOP and don't have initiative. If you flat, what do you do on a Q-high flop? If you raise, he often folds, and when he doesn't, he often misses the flop and folds to your c-bet.

More or less this.

Also, I think OP needs to spend a little time playing heads up poker online.

A lot of noobs continue to think in full-ring mode when they play a hand. When we are thinking in terms of full ring poker, we often are biased in terms of hand strength and tend to regard TPGK+ as strong hands and everything else being "weak" hands.

However, when you are playing heads up, that isn't the case.

Heads up, TT is a big hand especially if our villain has a LAG range. Heads up play has a lot to do with image and understanding your villain tendencies.

So TT in this spot is an EASY 3-bet pre. You isolate against a player with a wide range, and TT heads up vs a wide range is a big hand.

Does the TAG know the LAG is LAG?

If you're not averse to variance, I prolly call this spot. If the TAG had a real hand, even on tilt he's likely to make a standard 3bet here.

But because he's tilting, and he knows the LAG plays wide he is forcing the LAG to pick up a big hand and play for stacks with a mediocre / weak holding that is prolly marginally better than whatever the LAG is holding. He's looking to basically flip a coin here with a slight edge.

I call.

If OP doesn't know what "effective stack" is, then is he capable of providing accurate reads?

I wouldn't put much weight on the labels.

OP already posted this hand in his own Beginner's Forum containment thread, got the same feedback, didn't like it, so decided to start a thread here? lol.

Oh yeah, OP's first account got banned. So there's that.