I think Meloni (who is not a particularly nice person herself) has made the political calculation that in most of the world, including Italy, it's more palatable with the voters to stand up to Trump rather than lick his arse.
This is good, because if even right wing politicians realise this, then centrists and left leaning ones should definitely realise it.
I think the clown is going to find out that he's not going to get a lot of respect or time from other world leaders any more.