Treason is a really powerful crime that carries heavy consequences. Bribery at peace should still carry consequences but in some cases (countries) treason alone carries a death penalty. Bribery during peace maybe shouldn't carry such a steep penalty
Treason carries the death penalty in a lot of countries. But in most countries treason is poorly defined in law so it's difficult to say whether somebody actually did commit treason from a legal point of view because it's difficult to define what treason is.
Oftentimes it's just easier to fire them on bribery charges and prosecute them using the standard peace time legal standards.
But it's useful to call it treason on national television for PR reasons even if they never actually face treason charges.
*This is generally the case for most countries I have no idea how Ukraine defines treason.
No one should be forced to go to war, trying everything they can to escape it is understandable, the only bad thing is that this is something that only the rich can do, but in their place i would do the same.
You just highlighted the entire reason leaving isn't a fair and equitable decision - only those with the opportunity can afford to leave and others will have to shoulder the burden more because of those absences.
When everyone is facing an existential threat, leaving is the same as agreeing with the threat.