The bible also says that you can own slaves as long as they are from neighboring nations, that you can kill someone for working on the sabbath, that eating shellfish is an abomination, that you can't approach the altar of god if you have defected sight, etc.. etc..
Should we take those things seriously, if not why not?
Well those things are typically quoted by people who don't understand the bible to be fair. Slavery was different in biblical times as were the social and political aspects at the time compared to now whereby most of the slaves spoken of in the bible were prisoners of war.
I would encourage you to read
this on slavery, it's short, to the point and covers most of what I would say on the subject.
Regarding the points you made on the sabbath and shellfish etc, the key to understanding this issue is knowing that the Old Testament law was given to the nation of Israel, not to Christians. Some the laws were to reveal to the Israelites how to obey and please God (the 10 Commandments, e.g.) Some laws were to show the Israelites how to worship God and atone for sin (sacrificial system). Some of laws were intended to make the Israelites distinct from other nations (the food and clothing rules). As hard to believe as some of these laws were, remember that they were for the Israelites, not the Christian. This is the key here - none of the Old Testament law is binding on Christians today. When Jesus died on the cross, He put an end to the Old Testament law (Romans 10:4; Galatians 3:23–25; Ephesians 2:15) because He fulfilled it, completely. That of course doesn't mean the Christian is to go around murdering or stealing but to follow the example of Jesus and follow His teachings - "I Am the Way" He said.
So as long as your bigotry can be backed up by scripture we are all good?
Call it what you like, it doesn't change the fact of what the bible says. I suggest you take it up with God as He wrote the bible, He'd give you a much better explanation than me.
It's like these tax avoidance schemes that are in the news at the moment; avoiding tax is illegal but people try and get around it by interpreting the law in a certain way, the law hasn't changed, avoidance remains illegal but the interpretation has which (to some) justifies the act of robbing the tax man... to little success now if press reports are correct (not the best analogy but slightly topical I guess).