Why does the social security card degauss?

Yes, but not often. Social security cards with magnetic stripes are easy to degauss when put together with other bank cards, bus cards or magnetic objects.

That is, you can't view personal social security information when using it.

Now some social security stations have magnetizers, which can be magnetized in the window.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.