A very interesting post Rutu😊
I must admit, I didnt give it that much thought. My thoughts wandered towards some future storyline where Ashok and Shagun may have kids (I know, dont tell me how crazy I am 😆)
So, coming to your post. I tried to be objective as much as I could while formulating this response (keeping my bias for Raman aside, and obvious dislike for Ashok too).
I think the reason that conversation happened and Raman said what he said was: Ashok has been shown to be a man who wants to 'win' the labels that Raman once had. Be it Shagun's partner or the father to Raman's kids. If Shagun had won Ruhi's custody case, Ruhi would have ended up being Ashok's 'daughter' too. And I think Raman knows very well what motivates Ashok.
In the context of the current track, what Raman was insinuating was: just by calling yourself a 'father', you dont become one. If you were really a father, you wouldnt have hurt Ruhi like this. A parent would understand the implications of hurting a child more than someone who just wants to be called a parent.
The actual words that came out of Raman's words were, yes insulting, and very similar to what Shagun says.
But the difference is not between Shagun and Raman. The difference is between the targets this line was aimed at. Ishita wants to be a parent in every sense of the word and Shagun knows it. Ashok just wants to be known as the parent and Raman knows it. And that is why I don't think Raman's line was inapproriate.