It is, as usual, a bit more complicated than that. Of course there are hard-boiled imperialists there, as anywhere. But it is unlikely that even Putin himself is one, he just has his own agenda.
Russians are a nation with too dark a history in the last couple centuries (and of course before). They were oppressed by their own, killed by their many neighbours in millions, and the memory of this lives deep in them. The major driver for many of them is to avoid harm first of all, powered with fear of their own government and instilled fear of “foreign malign forces” (definition changes by the day, rather easily, driven by propaganda). It is not safe to be against the war, so naturally the majority goes with the flow.
Do they want to actually conquer neighbours? In a way, there is a sense of pride in belonging to the strongest gang in the hood. As in, it is better to be a part of said gang than be chased by it.
Source: am russian-born, with a lot of contacts in the country.
The 2014 events were driven by the really nasty people, proper “russian jihadists”, if you like. Cut-throats armed by Russia dealt a lot of damage in Eastern Ukraine. Most of them now are either dead or in prison for being too unpalatable for their own. Borodai is one of the few survivors, but he still retains the spirit.
Not sure if what he says is the real set of ideas behind all the war drama.
Don’t get me wrong, I am not saying that the rest of Duma/government are fluffy kittens, just that he is an extremist not necessarily reflective of the majority even in Duma.
Or maybe I am still too optimistic, after all these years.