The use of forum or forums can be argued both ways because it depends how people see the places and spaces they interact in.
As said already, fora is normally only used for ancient Roman/Latin meeting places.
Today, we see the primary meaning of forum as placeless and rather abstract because a forum is commonly a meeting without reference to the meetingplace:
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The international forum on climate change
This forum exists wherever those people meet.
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The conference provided a useful forum for the exchange of views and ideas.
While the conference is in a place, we don’t usually refer to the place where the conference is held, ie. it seems strange to say The hotel conference room provided a useful forum for the exchange of views and ideas.
All this change doesn’t mean that we should confuse a community of people with a forum as a meeting or meetingplace where our community of people meet to exchange ideas and opinions.