Where was there at shot taken a Newton? AFAICT, he explains how Newton's theory addressed the problem, but there is no shot taken. I've never heard of such a problem as people taking shots at Newton..

There's no single remark, it just seemed somewhat condescending

Maybe not "taking shots", but I also feel a general "ha, he missed that big one" attitude.

Newton was such a great scientist that he made his famous "I don't make hypotheses" statement in regards to the nature of gravity. Knowing the limits of your (current) knowledge is a fundamental trait of being a scientist (and a philosopher, e.g. see Wittgenstein's motto "Whereof one cannot speak, thereof one must be silent." and Socrates' analysis of the Oracle's answer to him.)

I don't. Technology had not yet progressed to the point that one could design experiments to test relativity. And such technology depends on insights from other areas of physics.

Quoting Cecil Adams (http://www.straightdope.com/columns/read/957/was-isaac-newto...),

[He] took six thousand years of disjointed fumbling and made it into a science. Two sciences, actually, physics and to a large extent mathematics.

Feeling any "ha, he" that he missed a development 200 years later loses perspective about what he did.

Yes. Although Newton did lose out on notation. Leibniz had the better notation for integrals and differentiation at around the same time.