I found this backgrounder quite interesting; it even explains some of your reactions that, at first, I didn't fully understand.

Why Dublin won't yield on the backstop - Eurointelligence

If border checks have to go up as a result of no deal, it may look materially the same, but it is politically a different story. For one thing, the responsibility for the debacle would rest squarely with London, particularly as seen from the narrow vantage point of Irish nationalism. The government in Dublin would still be shielded from Irish nationalists' accusation of having accepted some deal with London entailing the possibility of a return to border checks. To be clear, this is not just a question of appearances, but one of a possible revival of now-latent tensions in Irish politics, comporting a possible threat of Irish-on-Irish terrorism.

Just as importantly, the unspoken Irish gamble is that border checks as result of no deal would sooner or later be overcome. The hope is that the UK would find a no-deal relationship with the EU economically and politically so uncomfortable that reason would ultimately prevail. A chastened London would come back to the negotiating table to work out a deal with the EU entailing the restoration of an open inner-Irish border, this time for good.