On the one side, the Serbian president is exactly what the rest of the comments here describe him as, and worse. The situation would be infinitely better if he recognised Kosovo and moved on. Instead, he keeps the question open purely for his own political advantage, ensuring that the tensions remain at the expense of the people.
On the other side, Kosovo is a military industrial complex puppet state that they've cut ties with/lost control of (intentionally or otherwise). It has been ramping up its opportunistic bullying and provocative abuse of the minority population in the north, who as of last year have no representation at all in local government, and are pretty helpless.
The unfortunate victims at this point in time are the minority Serbs in northern Kosovo, and more widely, the general Serbian population, who just like in the case of Brexit are being held hostage by their predominantly older, state-owned TV-watching, voting population who overwhelmingly vote for Vucic. Meanwhile, weapons have been flooding into the region from both the east and the west at alarming rates for the last couple of years, so he must be useful to someone.
Nobody wants this, but war is money, so here we are.