Looks like the original raiser has a big hand and wants to dish out maximum punishment for the limper. Shoving might not be a horrible idea either because we maximize our expectation against hands like AK when they call pre and miss the flop, and JJ+ when an overcard flops we tend to lose some value, but they might stack off right now.

There's definitely a tendency for live players to snap off a shove here with a hand like Jacks or Queens, maybe even worse pairs because they put us on AK, or they call with AK because they put on us on a range that they either dominate or are flipping with.

In general 3x to 4x is good as a default but I'd tend to raise bigger with AA at looser games because you want to charge preflop where the biggest mistakes are usually made, and I'm sure multiway pots in 3bet pots are more common.