I am not quite sure why you should?

According to the Oxford English Dictionary:
The plural ‘forums’ relates to “a meeting or medium for an exchange of views” whereas ‘fora’ relates to “(in ancient Roman cities) a public square or marketplace used for judicial and other business.”

The Cambridge English Dictionary goes so far as to have an entry:
Forum -“a place on the Internet where people can leave messages or discuss particular subjects with other people at the same time:
Discussion forums are a way of contacting people with similar interests from all over the world.”

If you are not prepared to accept the view of those two august reference institutions then be resigned to further cringing.