From the perspective of the MySQL developers this may be the only way to handle feedback. If a lot of people use your software you're probably going to get a significant amount of bug reports.
If I'm in the shoes of the MySQL bug triage team you have many things to do: research important bugs, relay them to the development team or internal stakeholder, and to consolidate bugs. I don't know the details but user bug reports might be like drinking out of a fire hose and the current process of asking for more specifics and timing-out bug reports may be their personal way of handling them.
I don't think just closing bugs without a solution is ever acceptable. The end-goal is increasing user satisfaction with your software. If you close a bug without resolution, you're not satisfying users. Closing this bug they way they did only improves some QA benchmarks, it doesn't actually satisfy any users.
If I'm in the shoes of the MySQL bug triage team you have many things to do: research important bugs, relay them to the development team or internal stakeholder, and to consolidate bugs. I don't know the details but user bug reports might be like drinking out of a fire hose and the current process of asking for more specifics and timing-out bug reports may be their personal way of handling them.