I am not a lawyer, but I have a mind and can read. I have a copy of the US Constitution and refer to it from time to time. In this layman’s eyes the Senate filibuster rule is contrary to the word and spirit of the Constitution. What say ye???
Since the very beginning, the Senate has fancied themselves "the greatest deliberative body in the world". So they allowed unlimited debate, thinking it would only be used for good, by giving everyone a chance to speak their mind, *completely* if need be, rather than anyone being cut off in mid-thought by an autocrat banging a gavel up at the front, telling them to shut up.
It wasn't until mid-19th century that some Senators discovered that this "sufficient debate-time must be guaranteed" rule could be abused as a loophole to prevent debate from ever stopping on some bill, preventing the bill from ever being brought to a vote.