Because it's not recognized as a State by Israel and a few other countries.
And because that fact is quite salient in current geopolitical affairs.
It's a big game of cat, mouse, pride, and political points.
-> Around 30 member states of the UN also fail to recognize the statehood of Israel...
There are couple of entities in the game whose statehood is debated / contested.
Taiwan and Kosovo would be some other examples.
I mean, there is no "objective" list of countries everyone agrees on, nor how many are there in total. You're gonna upset some people regardless of which definition you choose.