Well right after he hangs up with "Don Juan" (the bald mexican boss) Gus said something like "I just spoke to the man responsible for the attack", and he explains to Mike that "he was trying to protect his business by protecting our business". So, maybe the cartel doesn't want Lalo out of prison and since he doesn't know Lalo in prison is still causing trouble to Gus business, and doesn't know either that Gus orchestrated Lalo's bail, maybe $7m is just too much for one guy at some point? During the episode, they're also explaining the DA's office never really expected the bail got paid, and $7m is gonna raise a lot of attention.
There's also something Gus said in another episode, like everything's happening to Lalo in this site of the border is his responsibility. Maybe the cartel thought "oh well he got caught, let's move on". But on the other hand, it's quite clear that while Gus business wise is "with the cartel", the Salacamancas are "in the cartel". Gus is a huge silent, trouble free money maker, while the Salamancas are causing a lot of trouble. Maybe we'll get a more solid explanation in the finale. And let's not forget Lalo initially going back to Mexico brought a lot of joy and relief to someone:
View attachment 262904