That's very true and the only way immigration laws will ever be enforced effectively is with the involvement of local, county and state law enforcement, cooperating with a federal government that intends to enforce the law.
The Feds will never hire enough personnel to enforce immigration law nationwide and they shouldn't. It has to involve law enforcement at all levels. And politicians who oppose that simply oppose enforcing immigration law.
Notice that the same folks who claim that immigration enforcement is strictly a federal matter never mention sanctuary cities and the blatant defiance of federal law.