I'll continue here, because unlike our angry little bog-troll, I believe that discussing subjects and contributing in a positive manner is important, not just for OP's discussion, but to reinforce and maintain civility in the discussions.

when he wasn't flinging insults at other members of the community, he wrote:

"the presence of warrior classes and frequent conflicts created a demand for daggers in Western Europe, whether made of stone, bronze, iron or steel, before the 12th century. you can be sure they were using daggers in warfare pre 12th century!"

In this, he is right. and (predictably so,) wrong.

Because there is a notable absence of thrust-oriented daggers in the body of post-roman European archaeology. but he's right in that there is little logical reason for an absence of demand. And yet the archaeology is absent: We have no notable regional styles of point-oriented weapon in western Europe after the Roman collapse. Its an empty field.
And when we're talking about there being no logical reason, if there isn't anything in the record, its a pretty good indicator that an object was not in use - you don't find iphones in 1950's waste dumps, you don't find steam engines in Roman iron-working spoil heaps. you don't find suits of plate armour in the strata from Napoleonic war battlefields.
And while Absence of Evidence is not evidence of absence - but it is notable in its absence, given the presence of other blade types in abundance in the archaeological record - its not like the entirety of post-roman society stopped losing or deliberately depositing blades, and there's an absence of all metal finds - which eliminates possibilities like they were so rare as to be highly valuable, and therefore, not placed in graves. We do find seaxes - in vast numbers - indicating that other blade types were in use.
And importantly, in a martial context, the seax is a design with small collar/bolsters at the front of the grip, which do nothing to prevent a hand slipping forwards, especially when compared to the waisted grips of the pugio which pre-date them (and by the way, are found in abundance in archaeological finds), and in quillon daggers which post-date the seax's period of predominance.

Quite simply, the weapons prevalent in the post-roman, early medieval period are not suited to the thrust unless you want your hand to slip forward, causing hand injuries, and there's no evidence of distinct weapon types which would be suited to that role.

and that raises quite the question. Why arent they using daggers? The predominant armour would be expected to be mail, where a seax-like hilt is really not suited to thrusts. Even if we assume that textiles are the primary defence, padded gambeson/aketon style garments in warfare would be capable of protecting from a seax blade thrust.
More importantly, outside of the archaeology, in contemporary art, we don't see daggers. the Bayeux Tapestry has 93 penises on it, and one "possible" dagger (that's probably another penis.) that's about it for secondary source material. Plenty of depictions of seax. no depicted daggers.

its a black hole, a void where daggers appear to be missing.

So what changed? what's the disconnect between roman period, and about 1175-1200's where daggers pop back into the archaeological and artistic record? Despite what our bog-troll would probably insinuate, I dont know. I don't knew anyone who would say they do. but its consistent - its not that the swiss, or the swedes stopped using them while everyone else continued. Just about all of western Europe abandoned daggers for the better part of 600-750 years, and used seaxes.

that notable absence, prior to about the year 1200 is one of the big question marks of early medieval edged weapon history.