It is common for Baptists to take the position that any passage in scripture that sounds like its saying baptism is required for salvation is referring to "Spirit baptism." [Examples, Acts 2:38, Gal 3:26-27...]
If this is really their belief, why do they even administer the "ordinance" (their term) of "Water baptism" at all? I mean if all references to baptism are really "spirit baptism" why even waste your time baptizing in water, and why make your beliefs about immersion and credo-baptism a distinctive to the point of calling yourself "Baptist" (and with a capital "B" to boot) if you don't think the baptism that is administered by men has any real relevance to salvation and that its only "spirit baptism" (which obviously can only be administered by God) that matters?
[Knowing my own perspective may help in formulating an answer I guess: I also believe in immersion and credo-baptism, and I believe that spirit baptism takes place in water baptism, never separate, neither before or after but always at the same time; the only exception being in Acts 10 when God diverged from the normative order to show Peter that Gentiles are acceptable candidates for baptism and not just Jews. Its possible, I suppose that Baptists mean the same thing(?) and so I guess knowing I believe this could help answer the question.]