Firstly, Magic and Science are not inherently mutually exclusive.

Secondly, just because Tinker has devoted his life to physics, does not mean that he refuses to acknowledge that magic exists (even if we assume they are mutually exclusive). He even has a bunch lines telling other heroes to keep their magic, because he has a better solution. (Laser beams).

Thirdly, I cannot stress enough how inaccurate it is to assume that an entire species of sentient beings has only one single defining characteristic. It seems only logical that Tinker's people would have nerds and jocks and hicks and so on, be it due to regional differences or religious preference or even just personal interest.