Why do Tu-95 Bear bombers keep flying over Alaska?

Answer 1

They don't actually fly over Alaska, but they do wander into US/NATO territory. It's basically Sabre rattling by the Russians, and is typically resolved with a fighter escort guiding them back into international airspace.

The Tu-95 has several roles, and most actually aren't employed as bombers. They're more often used for maritime surveillance, electronic intelligence, and similar roles.