dismissing something because you do not understand it, well... ; no.
That would indeed be a terrible and shortsighted thing to do.
But dismissing something because it is of so little import to the originator that they did not even put effort into ensuring that it was understood... That is far more reasonable.
As, I believe, is dismissing something that is done with a similar lack of ability, even if that result
is the best effort of it's originator to make sure it was understood, if dealing with concepts in which the knowledge of should have also been accompanied by knowledge of how to properly present them.
As a set of examples much better than your red herring...
Dismissing the opinions of a three year old on ponies due to the style of writing is unreasonable.
Dismissing the opinion of a three year old on quantum mechanics due to the style of writing is generally reasonable, though some strange exceptions may occur.
Dismissing the opinion of a college on quantum mechanics because they write like a three year old is generally reasonable, because if they were able to legitimately learn about it they should have also legitimately been able to learn how to present themselves.
Dismissing the opinion of an alien (or other non-native speaker) who is just learning our language on quantum mechanics because they write like a three year old is unreasonable.