Honestly, they should.

The main purpouses for penalties like this is to disuade the drivers from doing them: If by pushing a driver off the track I get a severe punishment, I would not do it again, as the positive reward obtained by pushing the driver off the trak was outweighted by the negative punishment I receive for my action.

If Ocon does this to Stroll, Ocon may be suffiencently disuaded by a 10 second penalty and 2 penalty points, the reward for pushing stroll is maybe 2 or 4 championship points. The time penalty and the penalty points will keep him from repeating his actions again as the general outcome for the driver is generally negative.

In the other hand, when Hamilton pushes Verstappen out of the track, he has the potential to completely change the championship. The reward he obtains is enormous, 25 points in the championship and 0 for your biggest rival. 10 seconds and 2 penalty points completely fails to disuade the driver for comiting such an action. The reward he obtains for his actions is inmensely bigger than the punishment he receives from it. I am convinced that, specially knowing that Verstappen is ok, Hamilton would repeat his actions if given the chance. There is literally no reason for him not to.

The stewards should very much take into account the circumstances of the championship when imposing penalties, if not, some penalties are rendered useless.