You cannot use Newton or Einstein as an example of a knowledgeable perspective and simultaneously ignore the fact that there exist more knowledgeable people today. That is a fallacy; you could just as well cite Aristotle or Thales or Zoroaster. They get worse as they get older, and that's not a coincidence.
1. You argue through authority, for a subject where believers are infamous for throwing out their reasoning capacity (even becoming creationists)? :-( (Is this some meta level humor?)
2. Do you remember that quote about "standing on the shoulders of giants"? Those two are a couple of the giants we stand on the shoulders of, today. That doesn't imply a claim about intelligence, more than being able to get through a science university education.
No, i think that the categorical statement of bleachedsleet (five levels up the tree) is a bit offending, to me it sounds exactly like if he was claiming absolute authority on the subject, which he obviously can't.
showing a counterexample is not a bad argument, at least not in mathematics.
2. bleachedsleet argument needs that intelligence is very correlated with rationality. Sadly, the correlation is probably quite far from 1. http://www.nytimes.com/2016/09/18/opinion/sunday/the-differe...
(Regarding 2: For instance, there is mental disease. For another, if you raise children with one specific set of answers and they don't see any criticism of those answers, you can make most of them believe in anything all their life. Including creationism.)
> They had less information available to them than we do today by a large margin. Their opinions and beliefs are inherently less trustworthy due to that.
i for one congratulate you for being smarter and more Knowledgeable than both Newton and Einstein.