Hopefully they change the names. Even if keeping the old names isn't legally trademark infringement (IANAL, so I don't know), using those names without Elastic's consent is a low blow.
That said, being able to make a fork if you disagree with the direction of an open source project is one of the great things about open source. AWS clearly has the resources, and the motivation to maintain a fork of Elasticsearch, at least they are making their fork open source instead of keeping it proprietary. It probably would have been a better situation if AWS had created some kind of reciprocal partnership with Elastic and Elastic hadn't felt the need to change the license, but it is likely too late for that now.
That said, being able to make a fork if you disagree with the direction of an open source project is one of the great things about open source. AWS clearly has the resources, and the motivation to maintain a fork of Elasticsearch, at least they are making their fork open source instead of keeping it proprietary. It probably would have been a better situation if AWS had created some kind of reciprocal partnership with Elastic and Elastic hadn't felt the need to change the license, but it is likely too late for that now.