All the Blizzard GMs are live humans who work for Blizzard directly. Most are at the Austin, TX Blizzard office. Blizzard does not outsource support.
They have always had limits. They are not allowed to give game hints, they are not Devs who fix bugs, they can’t intervene in loot disputes, etc. They can only do what is within policy and what is backed by game logs.
There is a whole article about what they can and can’t do on the CS forum.
They probably took that as a request for a game hint which means they would refer you to a site to read about the game.
The tools they used don’t require them to enter the game anymore for most things. They stopped doing the interactive tickets for most things back before WoD.
They DO have Live Chat and Phone Callback though for some Billing and Account Access issues.
If you have questions about what GMs can do for a specific issue the Customer Support forum is an Information Desk. https://us.forums.blizzard.com/en/wow/c/support/customer-support/13 You can get answers about how to best put in a ticket, what policies are in place, etc. There are no GMs there and it is not a replacement for a ticket, but they can help walk you through the process so you don’t waste your time.
This was not what you think. What tends to happen is that the GMs don’t know about new bugs or issues. If the logs look good to them, and there is no notice distributed to them about an issue existing, then they give the standard reply. However, once many reports start coming in it tends to get escalated to QA and then they get to the bottom of it. GM then get get new updated instructions. Which is what you got the last ticket. Bottom line - QA team, Dev Team, and GMs don’t relay information smoothly or quickly. GMs are last to find anything out so they don’t know of a new bug or what the protocol is for it until later.