Queuing has it's own definition, in that you can press an action before you can use it and it still goes off when it is first available. Macros do not interact with this at all and the devs have said as such in the past when people have asked about this (this is back in 2.0 days). They have specifically said they do not want people to use macros to essentially automate combat and so they do not behave the same as the actual actions.
Now, whilst I do not know exactly how it works, I can speculate how the queuing system works on the back end in a very simple example. GCD on cooldown, at some point the game goes, queue open, stores a single input (the last one pressed), queue closes, GCD is off cooldown, activate action. All a controlled environment as opposed to smashing the button (digitally speaking) which is just unnecessary processor usage. Macros are not counted as something that interacts with that system and so macros do not queue.
You see, this changes things. It is one thing to claim macros aren't bad, when everyone knows that they are and it is another to say, I have this condition, however, I have found a way to use macros to allow me to play/enjoy the game more. The difference here is that, you are trying to say, see macros aren't bad, I don't know what you are talking about, whereas, what you actually meant was, look, I know macros are bad, however, I have found a way to make them slightly less bad for people that need them for one reason or another.
So really, it is how you came across, 'look, I know you all think you know what is going on, however, I'm going to prove you all wrong with faulty testing and bad takes'. That is how you came across. If you had started it off with, look, I have a condition and am trying to make macros work slightly better for me, here is what I have found, I guarantee it would have been better received.
Macros work by executing every line in sequence irregardless of what it is. I just tested and it definitely makes a difference, even if in reality it is imperceivably.
(Test was done with 2 macros, macro 1 line 1 /echo 1, line 2 /echo 2. This just pastes 1 and 2 in chat that only you can see. Second macro was the same, except every line had a /micon Triplecast in every line except line 1 and 15. Then, just used them. You should be able to see the difference in time it takes. Note that you cannot leave any lines blank otherwise the macro will not work and break. I originally tried to test with blank lines and the 2 never came out).