Because he'd like to steal the oil.
Because Rubio is obsessed with "communism".
Because Maduro has been "mean" to him.
Because he'd like to immitate Putin and have something to brag about.
Because he has the biggest military machine on Earth and he's a bully.
But mostly because he thinks he can.

Because:

'like-minded “patriotic” parties' - i.e. fascists aligned with Putin.