In what way is it "unscientific"? That's an odd choice of words in this situation. What we're aiming for is rational and in this instance, it's perfectly rational to be suspicious based on an abductive argument and unproven extrapolation. As another commenter aptly noticed, once you're able to prove it, the harm has already been done.

Having read the original comment again, I can see how it can be interpreted as suggesting to avoid Zoom as a precautionary measure, rather than accusing Zoom of wrongdoing. However, plenty of people are treating this incident as proof that Zoom is lying about encryption.