tommjames:If a construction implies an idea that is comparative then how can you meaningfully say that that thing is not itself comparative?

I'm talking about the use of language and the focus of attention. I'm saying that "comparative" refers primarily to qualities, more than a simple sequence in time. The construction does not necessarily imply a comparative idea of 'earliness' unless this idea is intended to be in the foreground, and is usually in reference to some other event. Thus to say 'I came earlier than he' (for some important event) is not conveying quite the same message as 'I came before he did'. Pli frue would be used for the first, antaŭ ol for the second.

Right, so in other words it's not a formal comparison, i.e. the Comparative

No argument from me there. It's a fair point, but does "antaŭ ol" have to be a formal comparative in order to think of it as a comparison more generally? (Which is really all I was getting at). I don't think so.

The authors of Reta Vortaro appear to see it similarly:

ReVo:'Ol' estas ankaŭ uzata post vortoj, kiuj, kvankam ne estante formale komparativoj, tamen esprimas iele neegalecan komparon:

Trans:
Ol is also used after words which although not formally comparative, nevertheless in some way express a comparison of inequality:

[...] antaŭ ol vi venos al mi, li diros al mi la veron Z [...]

What Reta Vortaro describes as "iele neegalecan komparon" is I believe the same thing Bertilo speaks of in PMEG. I really see nothing suspect in any of this.

According to Piron, "antaŭ ol" is a Slavic construction:

Piron:While Esperanto allows us to say antaŭ ol foriri 'before leaving', it usually avoids post ol foriri 'after leaving', preferring the forms foririnte 'having left' or post foriro 'after departure'. In Russian they say prežde čem ujti 'before leaving', but not posle čem ujti 'after leaving' preferring instead ušedši 'having left' or posle ŭoda 'after departure'. Compare this with the symmetry of the English forms just quoted or, for example, with Spanish: antes de salir and despues de salir.

(Note that the redundant occurrence of ol 'than' in antaŭ ol foriri, literally 'before than to leave' — it would have been just as clear to say antaŭ foriri — comes by way of literal translation from the Russian prežde čem ujti, which shows the same čem (Esperanto: ol) as the expression bol'še čem on 'bigger than he' (Esperanto pli granda ol li.) In Esperanto we say por transdoni 'in order to transmit' but not pro transdoni 'because of to transmit', and in Russian čtoby peredat' but not iz-za peredat'. In Spanish, on the other hand, there is para transmitir and por transmitir.

tommjames:Right, so in other words it's not a formal comparison, i.e. the Comparative
No argument from me there. It's a fair point, but does "antaŭ ol" have to be a formal comparative in order to think of it as a comparison more generally? (Which is really all I was getting at). I don't think so.
The authors of Reta Vortaro appear to see it similarly..

There does seem to be more than one way of using the idea of 'comparison'. IMO making a long debate of it isn't worth it, so iru en paco; I think we understand each other's viewpoint well enough.