I think this is a bigger part of it. There are occasionally scandals that get media attention where someone got through the immigration system when they arguabl

I think this is a bigger part of it. There are occasionally scandals that get media attention where someone got through the immigration system when they arguably shouldn't have (past involvement with organized crime, etc.), which produces public pressure to add another check to make sure it doesn't happen again. So the system is oriented around an adversarial sort of approach: we think there's a good chance you probably shouldn't be here, and you need to go through this complex process to prove otherwise. The system is designed to find dozens of reasons to exclude the applicant (since voters demand excluding people for those reasons), so there are a ton of pitfalls. Which is where the immigration lawyers then come in, since an individual immigrant with no idea how the system is designed or what it's looking for has a high likelihood of stumbling into one of those pitfalls.