(1) One does not need to be canonized to be a saint.
(2) Not everyone who is canonized is a martyr - canonization does not equal martyrdom.
A question: why would this canonization be political? Clearly the forces of political correctness are marshaled against it, and there is little political advantage to canonizing a man the mainstream media are bent on demonizing.
Stepinac was an anti-Communist because he was a Christian believer and pastor. He was put on a show trial because he refused to join the Communists in subverting the Church. I suppose this was a political act from a Communist perspective, but from a Christian perspective it was the only thing to do.
2. Stepinac is an icon of the Croatian nationalism, as well as Catholicism is a part of it. Croation nationalists are eager for Stepinac to be canonized, it's issue of their appeasement, which would bring a political gain for Vatican in Croatia. The "PC forces" you mentioned are Serbs, who are Orthodox and are unlikely to convert to Catholicism, so their voices may be ignored.
3. Stepinac supported the Croatian Nazi state which existed during the WWII. While there's no evidence he was responsible for any nazi crimes himself. This makes him a controversial person.