What is true is that using the steemstem tags helps our curators. But this is not a requirement for getting some support from SteemSTEM.
For this specific case, if the honour members didn't react, it is maybe because the post was not reaching our guidelines or maybe because of an abusive behaviour.
Note that I don't defend anyone here as I only have a fraction of the information. I am just bringing in potential reasons why the post was ignored.
Anyways, the new curation system I am designing will actually merge posts carrying all tags related to the STEM fields. This should help.