Any indications this impacted their job performance?
uhm....having sex while on-duty is a massive dereliction of responsibility.
It definitely can be. But if you put a bunch of people in the same environment and they spend enough time together, eventually they will f*** each other soon enough.
Even purported workplace bans on sex are less total bans on it and rather requirements that you run it through HR.
There is no HR department or company that would be ok with employees having sex
on the clock/ which is the problem here
These firings are completely appropriate