They probably did checked but it was most likely complicated / subject to various limitations and with all those complications they decided to not provide services, like most US companies, that was pre 2018.
When a county is under embargo it's more complicated that just checking a website from the comfort of your chair, I remember many Iranians complaining about that but the chance that you're infringing some rules could lead to very very serious / expensive sanctions ( with DoJ / DoT ) it's just not worth it.
The fact that your company "did not even bother to check" is a poor argument for "everyone has to do it".