I'm Irish, and there's a lot of this in our society. It was much more accepted in my parents generation, and appears to be reducing a little bit as we become a richer society.
Now, all of them were born a generation after independence, so it's definitely not just that.
However, when the government has historically not given a crap about you (as the British government did not), it leads to a disconnect from the society and institutions that increases the probability that you'll be OK with tax dodging and not have as much trust in the overall society (because historically, it didn't care about you).
So, I'd say that it's slowly changing because we're not a colony anymore, but it definitely didn't just disappear in a puff of smoke in 1921.
We're the only horrifically-bent country in northern Europe
To be fair, though I'm not a fan of the authoritarianism, without the Catholic Church neither of my grand-parents or their parents would have had an education, and indeed the church was the centre of irish social life and community for a very long time.
Like, post-independence, the Church did a lot of dodgy things, but I really don't think you can blame the one organisation which actually provided some services for Irish catholics for our issues with authority.
And it's worth pointing out that much of the remaining corruption in Irish life is at the political level, rather than the bureaucratic level. As an example, you might bribe politicians to get planning permission for a large shopping centre, but you don't have to bribe the passport office for a renewal.
Can you give me some examples of Ireland being horrifically bent?
Edit: incidentally, thank you for Kildare Street!