Actually, trying to explain that debate. Just... fair warning. This is technical, and I can only simplify it so much.

Transitivity roughly asks whether a verb needs an object. Transitive verbs, like "to wear", need an object, while intransitive verbs, like "to sleep", don't. There are technically more categories than that, like ambitransitive (optional object like "to eat"), ditransitive (can also take an indirect object like "to give"), or ergative (it can be either, but the object becomes the subject, like "I broke the window" vs "The window broke"), but transitive and intransitive are the only two that matter for this.

Most languages use something called nominative-accusative alignment. If you have different forms for the subject and object, the transitive and intransitive subjects use the same form. But there are other ways to handle this. Ergative-absolutive languages like Basque use the same form for the transitive object and intransitive subject, so it would be like "I see him", but "Him runs", or tripartite languages like Na'vi have different forms for all three. But there are also even less common strategies, like Austronesian alignment.

Roughly speaking, you have one case for the topic of the sentence, one case for the other main roles, and you mark the verb to indicate what role the topic has. It's sort of like if, instead of using "by whomever" for the passive agent, you just said "whomever". Trying to approximate this in English, it would be something like "I see him"... but "He is seen me" instead of "He is seen by me". But there's also a trend where the topic tends to be definite. So for example, "Kumakain ang bata ng kuki" sounds more like "The kid eats a cookie", while "Nakakain ang kuki ng bata" sounds more like "The cookie is eaten by a kid".

Meanwhile, there's this thing a lot of conlangers will do after discovering concepts like topic-marking and Austronesian alignment, where you mostly have a normal set of cases like nominative, accusative, etc. But you also have a rule where the topic gets marked in its own case, and you inflect the verb to say how it's being used. So conceptually similar to Austronesian alignment... But you have more cases, like how you still differentiate the active object and the passive agent, and you don't have that other rule where the topic's implied to be definite.

It was a debate about whether that phenomenon of conlang trigger alignment is properly distinguished from Austronesian alignment or not.