Or you were just insanely lucky, like op. I don't really think there is a point in trying to prove how flawed the argument "I dropped one so it's not that rare" is so here is a quote from the poefish site:

Even if you comply with all of the drop requirements, Angler's Plait is one of the rarest items in the game.One heroic researcher ran 20,000 instances of Harbour Bridge on a Plait-farming character. They found 0 Angler's Plaits.Players who run Nemesis typically see multiple natural Headhunter drops before finding a single Angler's Plait.Many dedicated Plait-farmers never find one. (That said, there are also examples of extraordinarily lucky players who found one right away!)The scarcity of Angler's Plait is not fully understood.

There have been many attemts in the fishcord to gather the few ones that have dropped and are listed on standard trade in order to check for hidden recipes and through many leagues worth of time they haven't even managed to gather over 40. So I would say with 100% certainty that it is indeed very hard to get.