I am thinking of not-so-few legends of F1 that would be much less known if such life bans would have been issued sparingly.Intentionally ramming someone out of track should get you a ban. As easy as that, it doesn't matter they don't go that fast.
I have mixed feelings. On one hand, yeah, you behave like an idiot, go home and don't come back. On the other hand, the vast majority of the penal systems are supposed to work towards rehabilitation, so even if you kill somebody you may be free one day if you show that you have learned from your mistake. Having committed a good part of your life to a driving career and getting banned for life without chance of coming back for crash without much risk or consequences seems a bit disproportionate.
(If we open the attempted manslaughter pandora's box... soccer is going to be interesting, and much cleaner).
BTW, am I the only one that for a moment though there were radio control cars? They camera with people on the foreground makes them look tiny (watch without sound).