Yeah, those are pretty much what the creationists seize on to cast doubt on the Miller-Urey experiment. What they neglect to mention is that the "trap" was simply a way of concentrating the reactants that resulted from the atmosphere experiment so they could be analysed. The amino acids, etc, were formed in the experiment's putative reducing atmosphere
before being concentrated in the trap - thus proving that organic building blocks could be formed (i.e., the results proved the hypothesis correct). Creationists are being highly misleading by leaving out this little tidbit.
As to the atmospheric composition itself - yeah, most experimenters these days don't think that the early atmosphere was all that reducing. So the creationists are right on that. However, they're once again being disingenuous by neglecting to mention that other experiments over the last 50 years have even MORE impressive results using more "realistic" atmospheric compositions. Remember, Miller-Urey wasn't trying to create life - just biologically significant organic molecules from essentially inorganic chemistry. In that, they succeeded. Since then, we've found roughly the same flavors of amino acids etc in meteorites and the spectra of comets. Seems that this stuff is actually pretty easy to synthesize under a huge variety of conditions...