People on the internet criticize everything way too much, it's probably down to the time we live in where everyone is has a "freedom of speech" boner.
we should fully understand it first in order for our input to be valid.
A fantastic point. People need to realize that even though they have a right to an opinion, they need to have some knowledge about the subject for their opinion to be taken seriously.
I disagree. If it's a valid opinion it's a valid opinion, based on the merits of the opinion.
So if I never ate an apple in my life, can I say "in my opinion apples taste like crap"?
People would say yes I can because I have the right of freedom of speech, but all rights come with responsibilities, and it is my responsibility as a human being to educate myself before formulating an opinion.
How do you define "valid opinion" or the "merits" of an opinion? If someone doesn't understand much about the domain in question, how effective will their opinions be? Maybe they could repeat the opinions of others who have done the work to understand, but in that case it wouldn't really be their opinion anyway. It would be a repetition of someone else's opinion.