I was asked to sign a contract like that and I had my current employer change it so that it didn't include those lines/words.

I can't indemnify someone against patent lawsuits. I can't know whether the code I am writing that is coming out of my head is in a patent somewhere. Not only that, but the contract asked me to assign to the company any and all ideas/thoughts/previous work that may or may NOT be relevant to their line of business and that by signing I had agreed I had done so (not even to the best of my knowledge, so if I forgot to give them a text file that I wrote years ago with a great idea then I'd technically be in violation).

Under no circumstances am I going to sign over any part of my work prior to the employment contract, nor am I going to sign over work that is completed on my own personal equipment outside of company time that isn't for the company.

To me it just felt like they were overreaching, and the guy I was discussing this with told me that wasn't their intention and that I should just go ahead and sign it because they would never hold it against me, and I told him no, I told him to go fix it, then maybe I'd sign it.