The cause of WW1 was the mistaken view of empires of that time that they had to expand or die. Austrians being blocked by Prussia in the north and Italy in the south decided to pick on the corpse of the Ottoman Empire - yet it ran into the force empires have not had to deal with before - nationalisim. The natives of the Balkans did not want to be ruled by the Austrians or the Turks or the Russians - but to rule themselves.
I asked my dad about my uncle's disbelief and he said that unc was a good hearted soul but not very smart and I shouldn't pay too much attention to what he said because he didn't know very much other than what the union and his "fraternal brothers" told him and that they certainly had their own agenda.
Are you my uncle? He also had an animose toward Austrians generally and the monarchy specifically.
Again, I ask simply, if all Hungarians hated the House of Hapsburg so passionately, why did they restore their kingdom in 1920? Why did they work so hard to get Charles to return? Why did they turn out by the thousands in TWO efforts to restore him? Why are the Hapsburg heirs still welcomed in Hungary today?
The fact is, the Hungarian liberals had a problem with the ultra-conservative Hapsburg Emperor. Their revolt was not a success, not all Hungarians supported it and in any event was a hell of a long time before World War I.
At the outbreak of WW1 the only people hell-bent on expansion were the French republicains, who had been so humiliated in 1870 and wanted Alsace-Lorraine back so bad they were willing to do anything to get it.
However, it is interesting to see that, after the Hungarians, you are now sympathizing with poor Muslim Turkey for being "picked on" by those mean ol'Austrian Christians. And, btw, Russian rule of the Balkans was exactly the point. Do you really think they were coming to the aid of Serbia simply out of the goodness of their hearts?