The fact that people, who've had centuries to do it, can come up with justifications for their choices doesn't change the fact that this is what they are doing. Constructing justifications for not following clear instructions, in some cases explicit commands, that are no longer acceptable.
This: "The Bible clearly has a view as to what marriage is supposed to be, and both polygamy and divorce were concessions to the hard-heartedness of humans before Christ--concessions that are no longer acceptable, because there is no excuse, with the Holy Spirit in our hearts, for hard-heartedness."; doesn't even sound convincing. It's a superficial justification for no longer engaging in the polygamy that is common and accepted in the Bible.
Same goes for the bacon argument. I missed the part where Jesus said it was OK to eat bacon now. The original reasons for the rule aren't hard to understand, given the times. Things have changed and now we know better, and behave accordingly. Regardless of what the Bible says. Because we pick and choose.
As I said, thank god. Because if we didn't? That bit about killing your child for taking up other gods, and killing witches, and other fun bits? Those are very clear commands and aren't optional.
"And [Jesus] said to them, “Then are you also without understanding? Do you not see that whatever goes into a person from outside cannot defile him, since it enters not his heart but his stomach, and is expelled?” Thus he declared all foods clean." Mark 7:18-19 (ESV)