It's pretty heinous, of course -- "In no trial or hearing under this act shall the testimony of such alleged fugitive be admitted in evidence," for example -- but then we knew that. But to me the interesting thing is the refusal to call a slave a slave. Maybe there's some legal reason they can't, but I suspect it's just another example of euphemism. It's pre-Orwellian, you could say. In fact I'm sure "advanced interrogation techniques" were used on these "fugitives from service".
It also (and here wikipedia is again invaluable) was an expansion on the War on Fugitives:
And be it further enacted, That any person who shall knowingly and willingly obstruct, hinder, or prevent such claimant...or shall harbor or conceal such fugitive, so as to prevent the discovery and arrest of such person, ... shall, for either of said offences, be subject to a fine not exceeding one thousand dollars, and imprisonment not exceeding six months.In other words, even in the Northern states, you had to be on the side of the masters, or the persons in service or labor. The Northern states, apparently, did not like this. But the alternative was instability, and people will almost always choose a deteriorating stability over the unknown.
The Compromise of 1850 was the North's Munich, in a way; it just kicked the inevitable confrontation down the road. But (to be contrarian), maybe that's not so bad. There's something to be said for letting things disintegrate to the point where you have new people come in who have no interest in keeping the existing ways. Think Lincoln over Fillmore, or Roosevelt over Hoover, or Churchill over Chamberlain, or even, potentially, our own situation. Before that you'll try anything, even euphemism (or, to use a euphemism for eumphemism, "rebranding.")