Why is H2SO3 an acid when the oxygens have lone pairs?

[vuongnaomi1L]

So H2SO3 is an acid, but the lewis structure (which I inserted below) has lone pairs to attract H+ ions from H2O, which will make OH- ions. So why is it an acid and not a base? What makes H2SO3 lose H+ ions but not attract them?

[Carolina 3E]

SO3^2- has 2 oxygens with a formal charge of -1 and those are the sites where H+ from H2O will form HSO3- or H2SO3. That makes SO3^2- a base.

[Dylan_Nguyen_2C]

I think in this case the SO3^2- is the Lewis base because the oxygens bonded to the central atom have already donated an electron pair to accept an H+ atom. This would make H2SO4 the conjugate acid to an SO4^2- molecule that has already accepted an H+ proton, feel free to correct me if I'm wrong though. Hope this helps