Yes, I guess that would have been more precise. Claiming that the fathers all or mostly taught it and that it's in Scripture would at least imply that they believe it constitutes divine revelation. While I accept what Meg said as true, maybe they didn't come out and say the word Dogma, they treat it as if it's part of our faith which to deny would make one not Catholic.
Well, if flat-earthers have implied that one would not be Catholic if one denies the flat earth, then of course you are justified in calling them out on that. I have seen that flat-earthers can take things too far. But please don't take it one step further.
IMO, it is an interpretation of Scripture that the earth is flat, and it is not invalid, for the reason that there were Church Fathers who believed in a flat earth. That doesn't mean that there was a general consensus at all.
I have seen the scriptural passages, and to me, they lend themselves to a flat -earth.
On another subject, though not unrelated, it was, however, a consensus of the Church that the Earth was at the center of the universe, and that the sun and other planets rotated around the earth. This however would not now be taken as fact by most Catholics, or even traditional Catholics.