No, Congress did that. A Democratic Congress. Bad enough they had to lie to Reagan to get him to sign it.
To say that “any Republican who would do that today etc.” implies that everyone was further left back when Simpson-Mazzoli became law.
Yes congress did that. But Reagan fell for the lies and did not try enough vetoes to stop them. If had, and congress overrides the vetoes, my respect for Reagan would be triple higher from my already high respect for him.
Overall, Reagan was a very good and effective president. But I can not bury my head in the sand over the instant and general amnesty to illegals and tripling the size of federal spending.