Your comment is an embarrassment to FR:
Each House may determine the Rules of its Proceedings, ... [Art I, Sec 5, Clause 2]ML/NJ
Do you really believe the founding fathers meant for the senate to operate the way it does today? Do you think the article/section you quote means they can give themselves pay raises and medical care only royalty would have? Yes, the constitution says they can make their own rules but that was before the citizens decided to let them be elected (bought and paid for) instead of appointed by the governor. If it was still that way Nelson would be out of office today because the Nebraska governor would have made a phone call and said “Get your lousy ass back here. Or you can stay there if you want. But not as our senator!”