Well, it's actually easy. 45+ years old people were born and raised in the Soviet Union, served in the Red Army. So, some of them support Russia. It's quite easy to watch Russian channels in Ukraine, thus they are affected by Russian propaganda. They willingly sells information to Russia.

On the other hand, it is an opportunity to get money. The majority of 'traitors' has nothing.
A few examples:
Denis Pushilin - the head of Donetsk Republic. He ran multilevel marketing schemes and stole money from people. Now he controls mines in Donetsk and the whole Republic. His daughter is finally able to afford vacations on yachts in Dubai and Abu Dhabi.
Kirill Stremousov (killed) - anti-vaxxer, conspiracy theorist, blogger and traveler. Putin appointed him as a head of Kherson.
Every single one of them like that. Opportunists.