Earlier quoted context omitted.
They would want to avoid escalation. Escalation with cartels historically does not go well for anyone involved.
Escalation by attacking US civilians or the homeland has also gone poorly. It’s been the casus belli many times, notably ending in two Japanese cities getting nuked…
You're forgetting all the times the US failed too, and those cases weren't even on its own border. Iraq, Afghanistan, Vietnam... the list is very long. Creating an existential threat on your own border is a bad move for anyone. Remember how bad Columbia got? I guess not. The current situation has the potential to be much more dangerous.