Serious is not any kind of parameter. It means nothing.
There are significant numbers of virologists and medical experts on both side of the issue.
There is still debate on the effectiveness of separation, masks and isolation.
I don't see this as even debatable. However, if some chose to think that all is solved, welcome.
I think he means professional virologists and other credentialled professionals to "debate" on a subject like communicable disease spread... VS just some dudes chatting on the internet or on a couch somewhere.
When you say, "There is still serious debate whether masks are even effective." ... the "serious" part seems to indicate that there are differing groups of credible researchers out there. That is something I have not seen.
"Serious" research is usually co-signed by several who agree with the findings. I would love to see a citation from a cadre you can bring up here. I