What's the workable alternative though? How many years did successive Tory governments throw at the NI trilemma, only to find nothing more viable than May's Backstop, which is nothing more than what Johnson signed up to only with the proviso that it would have an end once technology was developed that would render it unnecessary? Tory Brexiters insisted the technology existed already so the Backstop wasn't needed... and yet mysteriously it hasn't been deployed to the border yet?
Once again, there literally isn't a way to square a hard Brexit, the GFA, and maintaining the integrity of the UK. The Government chose to sign up to the first two, whilst deciding to try to squeeze the third in through the back door and hope the EU didn't notice.
Or rather, knowing that the EU would notice, but the narrative could be created that attempting to enforce the deal the UK negoiated and agreed to was the EU continuing to punish the UK for daring to leave. When you have people on here accusing the EU of "playing silly buggers over NI" instead of pointing the finger at Boris and his cronies for selling them a lemon it tells you all you need to know.
Leavers: The Brexit campaign lied about what they could achieve and what benefits the country would have. The architects of such carried on lying to bring down May, they lied to gain a majority and they're lying to you now as to why what they promised isn't working.