Probably because the last time the USA tried something like this, they lost 8 soldiers and about the same number of helicopters.
This happened 45 years ago, with different gear, and a lot of operations between now and then. It should have zero impact on any decision to go into Iran or not.
Of course, whether the US would go in is still a valid question, including other aspects of risk.
(mind you, the idea that a raid on a fortified facility, rather than lightly or undefended civilian buildings, would be an easy win, is the real delusion)
The entire point of making the comparison to "doing the same thing in another country" rather than nothing or some alternative course of action was to head off this specific nitpick.
The US already tried that thing once in the early days of the current regime (literally linked in the comment I initially replied to!) and it's one of the bigger reasons we don't have normalized relations with them, though it's perhaps a distant second to the 800lb gorilla with a little hat in the region.
After all, you're supposed to police your own residents, and keep them from invading embassies, which are foreign turf. You're also supposed to respect that aspect of diplomacy. Letting your citizens raid an embassy and kidnap diplomats is the act of a banana republic, and definitely signals the end of diplomacy.
If the current regime is upset at someone trying to rescue their own people kidnapped from their embassy, then frankly that regime is insane. Iran is 100% at fault for allowing that to happen, not working quickly to resolve it. The US is 100% correct to have sent people in to rescue their own people, under those circumstances.
If the embassy was better armed, with more security, they'd be completely correct to shoot-to-kill every single person who stormed that embassy. Yet sending people in to rescue them after the fact is... wrong?
Hardly, and I sincerely doubt Iran is significantly upset still. Yelling about it, sure. Upset for real? No.
After all, it was a spectacular failure.