Hey there!

No, it doesn’t contradict it. The big point of the article is to point out this min.insync.replicas behavior. The definition says:
> min.insync.replicas is a config on the broker that denotes the minimum number of in-sync replicas required to exist for a broker to allow acks=all requests.

> the minimum number of in-sync replicas required to exist for a broker to allow

The key words are “for a broker to allow”. If more in-sync replicas exist, the `acks=all` requests will still be allowed.
min.insync.replicas does not change the number of brokers needed to acknowledge. It is just the minimum number required to allow such type of a request