"as" or "than" in comparative constructions

As.

There are two different constructions:

More/less ... than ...

As ... as ...

We do not usually mix them, though I'm sure you can find plenty of examples where somebody launches into a long comparison, and by the time they get to that point they've forgotten which construction they were using, and say than even though they started with as.

It seems to me that the only possibilities of connection are "rather than", "more than" and "less than".

• Twice as many men said they liked action movies rather than comedies.

• Twice as many customers ordered pizza rather than Ceasar Salad.

If you say "they like action movies as comedies", then they like them in the same way (which is not saying something very sensible). If you say "they like action movies than comedies" a comparison term is missing (less, more).

Addition in the light of what the other answers could suggest

There has to be a reference for the proportion; the number of men has to be twice as many as something. This something could be stated before. Then there is apparently no other solution than a statement as shown below.

• Quite a few men said they liked television. Twice as many men said they liked action movies rather/more/less than comedies.

The reference can be stated after, within the sentence. For this case also the reference can be one different from one having to do with action movies and comedies.

• Twice as many men as men who said they liked television said they liked action movies rather/more/less than comedies.

However, a reference having to do with comedies is also an option. The following construction makes "as" inescapable, and it is the standard construction; repetitions seem unavoidable.

• Twice as many men [as men who said they liked comedies] (said they liked action movies).

The OP's sentence is a transformation of this standard form through inversion (braces and parentheses) and elimination (bold type).

• Twice as many men [as men who said they liked comedies] (said they liked action movies).           ↓

• Twice as many men (said they liked action movies)[as men who said they liked comedies].           ↓

• Twice as many men said they liked action movies as comedies].

The ellipsis of "men who said they liked does not appear justified: to begin with the subject of "said" is not the same.

It is probably the incongruity that results from this transformation that is the cause of the uneasiness; personally I find the "compressed" form (also a cause of uneasiness to me) too suppressive of the usual relations.

It is in fact possible to construct a sentence in which the role of "as" is ambiguous; even though in the particular example of ambiguity that is provided below, the context is a trifle far-fetched, the undecidability stands out. This shows that sense is decided through the intermediary of the meaning of the nouns being used, which makes the initial construction a difficult one to handle in certain cases. It shows also that it is a construction that is deprived of any of the characteristics that give its unique meaning to the initial one (from which it stems).

• A small group of men said they liked reading spy stories. Twice as many men said they liked historical novels as history.

The basic undeleted structure of the first sentence is

• Twice as many men said they liked action movies than said they liked comedies. cf
• More men said they liked action movies than said they liked comedies. cf
• More men voted for A than voted for B. / More did A than did B.

I'm not happy with the suggested deletion here, whichever word is chosen; you can't like A than B or in everyday English like A as B.

......................

But with

• Twice as many customers ordered pizza as/than Caesar Salad.

the undeleted 'original' is

• Twice as many customers ordered pizza as/than [customers] ordered Caesar Salad.

(1) Comparing with 'More people did A than [did] B', we might expect 'than' to be the logical choice here.

And here are examples from Collecting Data - Amazon AWS rstudio-pubs-static and Ben Allen at WITF, respectively:

• Of more than 7500 callers, more than twice as many voted for Rudyard Kipling's 'If' than for any other poem.
• More than twice as many people died from drug overdoses than traffic accidents in 2014.

(2) But mimicking the less demanding sentence 'As many customers ordered pizza as ordered Caesar Salad.' might lead to the choice of 'as'; English is not always logical in its development.

For instance, the following examples are from articles by By Katharine Q. Seelye and Janet Elder in the NY Times, in the Planning Council, in the NY Magazine, 2007, and on Twitter by Steve Haroz respectively:

• Mar 3, 2004 — And in California, 2 in 10 voters were independents, and almost twice as many voted for Mr. Kerry as for Mr. Edwards
• In the five year period from 2003 through 2007, twice as many people died from suicide as homicide.
• ...twice as many people died from ostriches as from sharks (8) ... [and 250 from toasters] ...
• Twice as many people died from COVID in 2020 as died from fires in a typical year.

(Note the different deletion patterns, including the non-deletion of the repeated verb variant in the last example.)

Conclusion: There aren't many results to be found in the Google searches I did ("twice as many voted for", "twice as many people died from") but the more popular usage is the one with 'as', though the more logical usage is also found on occasion.