I think that's an uninformed metaphor because it assumes both math is totally foreign and should be able to be read by anyone. if you write code for a server that handles HTTP requests you wouldn't explain the guts of HTTP in your comments, you'd just assume if the reader wants to know more they'll figure it out themselves.

I think sometimes mathematical definitions, especially advanced ones that rely on simpler definitions, are too complicated/long to recant every time you use them, which you have to. If I want to prove something relating or relying on uniform continuity I don't want to state the definition every time both because its repetitive and because definitions often use the same notation, so I don't want my uniform continuity deltas and epsilons getting confused with my normal continuity epsilons and deltas. Try proving advanced things about field extensions and galois theory using induction like that and you may actually run out of symbols.

That being said it is hard to read real math writing/research which can be both dense and obtuse even if you're used to it. Maybe that's why you need a PhD to consider entering the field.