The reasoning seems a bit loose.

Maybe they are being targeted, and are yet undetected.

Maybe Russians have otherwise successfully found vulns jn Telegram enough (or other vectors) that it doesn't require high effort targeting for now.

Maybe the company's founders/employees are not considered that powerful in Russia's eyes.

At least if you are in the West and you use Russian VPN (or other similar services) to do something shady:

you are practically guaranteed that the service owners won't be compelled to assist the authorities.

Now with Telegram you have both risks:

- they can get pressure from Russia through family.

- they can get pressure from the West through the law / court.

I wonder what your thoughts on TikTok are.