Exodus 19 is the lead-in to the Ten Commandments passage, which I haven't decided how much detail I'm going to go into regarding it. It will probably take more than one entry, but whether it might be worth going really deep and making three, four, maybe even as much as ten, that remains to be seen. I suppose I have to decide what role I am to play in relating that information.
Here in this chapter, though, the first thing the SAB notes is God's promise of favor to the Israelites. I suppose one could see this as unjust and intolerant, as the SAB labels it, but at the very least, let's not forget that this is not arbitrary. If you read the whole verse, you see an "if" in it--this is a conditional state for the nation of Israel, contingent upon their fulfilling their part of the contract. If they do fulfill their part, they will become "a kingdom of priests", which is an odd turn of phrase. I think this is something that has to be taken figuratively to some degree, because reading all of the Mosaic Law makes it clear that only certain people can literally be priests. Defined very loosely, though, a priest is someone who is qualified to act as an intercessor between God and man, and the purpose of the nation of Israel according to Christian theology (and probably many branches of Judaic thought as well) is that all the other nations would see the special relationship between God and Israel and come to know God better by observing them. In this sense, every observant Jew is a priest.
Now God gives some warnings that nobody but Moses is allowed on Mt. Sinai. Penalties for breaching this law are severe; any man or animal that touches the mountain will be put to death. The SAB has an interesting speculation on this, one that I myself have considered in the past. Maybe Moses is going up on the mountain and meeting with nobody at all, and he figures that the best way to keep his cover from being blown is to keep everybody off of the mountain. If this is so, it doesn't seem to make much sense to punish animals as well, but perhaps it's just Moses' paranoia? I think the real problem with this is that the supernatural aspect is still apparent, and would need to be explained away. There's the column of smoke, which apparently at this time sits on the mountain, and there is the voice of God, and a show of power of some sort that the people experience. Still, an interesting thought no doubt.
The SAB also notes that Moses tells the men to not have sex for three days. I'm not sure why this is sexist, since there is no statement that somehow having sex will make them unclean because they touched a woman. Frankly, I have no idea what this is about, because no explanation is given.
The last note here is that God warns Moses to make sure nobody tries to sneak in and see God, because doing so will cause them to die. This is something that is mentioned a number of times throughout the Bible, and no explanation is given for it either. I don't think the "cruelty" tag is appropriate, nor really the "injustice" one, although I'd grant the "absurd". The fact that seeing God will cause one to die is generally presented not so much as God being mean and demanding privacy or whatever Steve Wells might be guessing, but rather a supernatural thing, that the mere act of laying eyes upon God in his full glory would be too much to take. It's another thing I don't fully understand, and certainly won't try to give an explanation for it.