Whether it's an unreasonable goal or not is debatable. On Balmung, at least, PF groups have been clearing EX Primals on day 1 since 2.2 introduced Leviathan. With cross server PF, I don't really think it's that unthinkable to clear an EX Primal on day 1 through the use of PF. Savage is likely a different story and I would agree with your assessment that a static is required if you want to try it on day 1 and hope to clear it. However, EX Primals have never been on the same level as Savage or Coil.
OP posted while frustrated and I can completely understand that frustration. One of the players in OPs group posted a tale of an AST in their party that wiped the run to Southern Cross and then claimed he didn't know what to do because he had never been that far before... in a clear party. Also, you're right, there are no video guides... so why are people joining clear groups when they haven't been through the fight and have no idea what is waiting for them. It's an incredibly rude thing to do but happens quite frequently. Pair that with the jump ship mentality that leads to everyone rapidly dropping party as soon as you exit an instance and I can absolutely understand OPs frustrations. While the OP was heavy handed in their initial post by berating the community as a whole, a subset of the community absolutely did ruin it for them whether it sounds nice or not.
It boggles my mind that people who knowingly join parties beyond their current skill level get more of a pass than someone who had a goal they wanted to achieve and posted appropriately labeled party finders to achieve said goal.
In addition, if we want to dissect things that could easily be considered "not very nice", of the two people I directly quoted, one implied on Page 2 or 3 that OP was on welfare to play video games all day the other ended their quote with the quintessential internet insult of "Go outside" after a long rant which included an analogy about getting matched with A+ players in duty finder... thus kind of proving that the clear party Party Finder was a completely missed point.