There’s a fine line here. Passengers must obey all lawful crew instructions. Those relate to the safe operating of the aircraft. Filming may or may not have something to do with the safe operation of the aircraft. If you are filiming entry/exit procedures to the coughpit, or how the crew access their sleeping quarters, that may be considered a safety related issue. Etc.
But the fine line comes in because you also can’t interfere with crew member duties. If you start getting into an argument with a crew member about your rights, you may cross the line of interfering with their duties.
A polite refusal to obey a crew member instruction to move seats to allow a couple on honeymoon to sit together, or to close the window shade if you want to look out, or to raise your seatback because the person behind doesn’t like it, is unlikely to have you in breach of obeying a crew member instruction. Those aren’t safety related. In Dr Dow’s case, whether it was the gate agent or crew who asked him to leave, they weren’t doing so lawfully. So he wasn’t in breach of that rule (despite it being a crew instruction to leave).
Get into an argument with the crew and the situation could change, quite quickly.
What happens after that would be a matter for the courts to decide, if it got that far. If the crew were acting unreasonably, there may be no punishment. But you’ll have wasted a lot of your time, and probably delayed yourself by quite a few hours.
I think filming does have a place. Again, Dr Dao’s situation is a good example. Supposedly in this case another passenger complained about the filming, and that’s why the crew asked filming to cease. Is that a lawful request if filming is allowed?