It's a rallying call. Every nation under the sun does it when they're at war. Propaganda is a tool where if you're not using it then you're not fighting hard enough. Russia, Ukraine, hell even NATO countries are doing it.
You know those leaked calls where we hear the worst of the Russians? That's propaganda, but they are also true. Propaganda isn't always lying. Hell, most of the time it isn't. It is selective truths. How many calls are not being leaked where both sides of the call are "GTFO of there." or just ordinary soldiers calling home?
Or when we are shown the craziest of Russian tv talking about doing the worst? That's also propaganda to Russia and also to us.
When it comes to Zelensky you have to ask when he is speaking "What's his audience?" when it is a rallying call it's to the people of Ukraine, when it is more neutral tone it is towards the community unless he's after something then he might make a more intense speech and rhetoric.
He wants Ukraine back, but if you read what he says outside of rallying calls he's always talking about taking Ukraine in a peace deal, not in a pitched battle. Because the latter is suicide. It took the Germans half a year to take Servastepol. Those forts are still there and the place even at the best of times was one of the few parts of Ukraine that leaned to Russia. Now it's fully within Russian sphere as those who didn't want to be part of Russia fled. It would be the meat grinder and well within black sea fleet firing range.