I am legally allowed to let my time expire in a chess game. This is not against chess rules.
If another player agrees to time controls then that player also agrees the other person might use up all of their time. A player consents, when agreeing to time controls for a game, that they may have to wait for their opponent to use up all of that time before winning on time. Again, this is not against official chess rules.
Banning or limiting player access to chess on this website based solely on using up one's allotted time, however one sees fit, is unfair and not in accordance with chess rules.
Stop trying to control how a player uses his/her time. If a person consents to a game, they are obligated to allowed their opponent that opponent's remaining time, and lichess nor you have any say in how that person uses their time. If you don't want to wait for someone to run out their clock, then don't accept long games. If you accept long games and someone runs out their clock, start another game or just wait. Deal with it. If I accept a 30 minute game, for example, then I had better be prepared to sit there for up to 30 minutes of my opponent's time, and I have no say or control over how the opponent uses his/her time.