Strict equality of opportunity is a pure lottery, which is just as absurd (if not more) as strict equality of outcome. Otherwise, it is claiming that certain factors (maybe, genetics or upbringing or geographic location or whatever else) should contribute to inequality of outcome, while others should not. The whole phrase, therefore, is a thought terminating phrase, allowing a speaker to ignore the nuance of which specific inequalities they belive are just vs not just, and why.