It is semi ironic that you claim philosophy requires more abstract thinking, (or a different "kind" which physics students are not good at) when mathematical argumentation, the kind that physics and mathematics majors have to live and breathe, may as well be the definition of abstract thought. By definition, Philosophical arguments in themselves are less logically rigorous than that of math and physics by virtue of the fact that they employ the use of the ill-defined words (comparatively speaking) of standard language.
The fact that physics and mathematics are actually more abstract and logically rigorous than philosophical argumentation implies that if a successful physics major does not succeed in a philosophy course, it's not because the material somehow requires more "abstract thinking," but must be due to some other reason. My guess, they think it is a waste of time.
Look, I majored in philosophy, and while it most certainly does not make me an expert on the field, your defense of its difficulty is just a variation the popular wisdom that people who excel in the hard sciences lack communication skills, are clumsy, and are not "people persons, " almost by definition. Fine, if you want to say that success in the hard sciences somehow implies one lacks the "capacity for abstract thought" that a degree in philosophy requires so be it, but more often I find that that line of thought is just a defense mechanism for people who do not succeed in the hard sciences.
I like philosophy, and I think it's an intellectually worthwhile pursuit, but it's just not as difficult, or abstract, or rigorous, however you want to say it, as math or physics.