It's fair to make observations based on our own experience. We don't have to be holding Masters degrees to form opinions or draw conclusions.
That's certainly true in some cases; it depends on the circumstances, context, and situation and whether the observations are presented as our own or whether they are presented as established fact.
Try going to court and testifying against somebody in vague terms with no backing. The situation I was in with the JW was not casual; it was really serious. He made a vague statement and presented it as established fact - not as an opinion based on his own observation. That kind of statement in that context does need backing up.
And, you're right about not needing master's degrees to form opinions or draw conclusions. It's really easy to form opinions and draw conclusions. People do it all the time.
For example, a number of white people are of the opinion that blacks are inferior to whites. They don't need master's degrees to form that opinion. They don't even need high school degrees to form that opinion. But, anyone to whom they state such has the right to ask exactly what is meant by "inferior" and to demand evidence to back up such a broad, sweeping statement that is certainly nowhere near established.
So, again, we can and do form opinions all the time without master's degrees, but if our opinions are vague and not backed up by evidence, and especially if they're controversial and the acceptance of them could affect lives, we should at the very least present them as opinion and not as fact, and we should be prepared to back them up.