GDAX moving to "post only", how can this possibly work?

When GDAX experienced perfs issue (during the spike to 19600 USD or so) they said they were restricting trading and only allowing "post only" orders.

So everybody becomes a maker. If everybody is a maker, there are no takers.

How then does any transaction even get executed then if there are only makers?

Did any transaction happen during that temporary restriction to "post only" and, if so, who are the takers?

To me this makes no sense at all whatsoever.

Cryptoflame