Why is the British media unhappy with Biden's Irish visit?

Is this the 6 counties?

What particular religion do you support for Ireland.

If I remember correctly, I'm sure you will correct me, that not all Irish nationolists were Catholic?

They were Irish. Full stop

Ireland is influencing the US trade relationship with the UK. And boy do they know it. Not even Johnson was brave enough to mess with the GFA.

The British as a society, to an extent hard to understand from an Irish perspective, are obsessed with status and hierarchy. Where you live, who your family are, what car you drive, where you went to school, where you went to college, where you work, where you holiday, who you socialise with, how wealthy you are, whether you are old money or nouveau riche, and what accent you speak with, all of these are constantly being evaluated and assessed when the British interact with each other. Having a title, or a CBE or MBE or whatever, matters. Think of the value system of Pride and Prejudice and you're not far off. Everyone "knows their place", in the sense that they know where they are in the pecking order. Those at the top of the hierarchy are used to, and expect, a level of fawning deference far beyond what is normal in Ireland. These people, culturally, are not remotely egalitarian, and they are very sensitive to any challenge or snub to their exalted positions at the top of the heap. This carries over to the perceived status of their "kingdom", the UK. They are personally invested in it. So when a US President spends time with what they see as a country of inferior status, they can't help but see it as a snub. Lashing out at their perception of Biden's rudeness is curious too, in that they feel entitled to upbraid him for his temerity. They still feel that the US is one step away from being one of their (inferior) colonies, and so they can still be rebuked for not properly acknowledging their betters. It's absolutely laughable. (The same attitudes to status and hierarchy (IMO anyway) explain the constant clashes with and hatred of the institutions of the EU - culturally, they simply don't mesh.)

I've lived there for years myself, and have also interacted with some of those in the upper echelons both in the business world and in diplomatic circles. I have quite a few British friends who would agree with the bones of my analysis.

but that was a Labour led U.K., and not the posh toff Tory party that took over in 2011. And then 5 years later Brexit happened.