Yes, strange. They cancelled their presidential elections this year so what`s the matter?
They did not outright cancel them - they are unconstitutional, but only during war. The problem is, Ukraine has not declared a state of war, but something instead in the middle. Roughly translated, it means "Military State".
Though he mentions the constitution, Zelensky makes more of an accent on the fact that many people are displaced, living within occupied territories, or are simply abroad. His argument is that elections in this context are impractical.
So the elections are not the reason. The reasons are:
1) First and foremost it is a politically explosive topic. The average Ukrainian now views being recruited as akin to a death sentence. Women go out onto the streets to block military recruiters from entering their villages and stealing their husbands and sons. There is no feeling that the war will end soon, or that the government will take care of you.
2) No money. EU aid is $50B over 4 years. US aid got cancelled. Japan and South Korea provided a few billion more. That's it - there are no more sources of funding except the IMF and the World Bank. Both the IMF and World Bank had conditions in order to continue the disbursements - conditions Ukraine will be hard pressed to meet. To pay for mobilization, Zelensky needs to raise taxes, raise more debt, and cut spending on social programs.
3) No weapons to arm another 500k men with. Ukraine still has maybe 60-70% of the equipment that was handed over for the counteroffensive. However, there's no indication that there will be huge transfers on the level of 2022-2023, that could outfit such a huge force.
4) The economy might collapse. This one is sort of self explanatory.