There are always tradeoffs, and the alternative requires time, people, and money that El Salvador simply does not have.

They don't have the luxury to enforce due process. When your house is on fire, you don't form a committee to discuss, debate, and vote on which exits your children should take; you grab your kids, throw them on your shoulders, and get out through the closest door or window available.

El Salvador has been metaphorically on fire for a long time, and Bukele was the first president to finally treat it as the emergency it is. Yes, corrupt political leaders often create more "emergencies" in order to keep themselves in power, and if that happens with Bukele then we can talk about that at that time. But crying wolf when he is actually benefitting his people more than any other political leader on the planet is very unhelpful.