This is absolute BS. There is a very strong correlation between LSAT scores and success as a lawyer. Ask any Wall Street law firm and they will tell you that it is a strong predicter of success.
higher LSAT score means better law schools which means better teachers, brighter peers, higher prestige, better offers down the road, better firms, more support/resouces.
i.e.: better lawyer.
not in all cases, of course. but it does help overall.