Calling play-doh or silly-putty a "gel" sounds a lot like calling glass a liquid to me. It may or may not be true in a technical sense (my chemistry is too stale to know for sure without looking it up), but not in any practical sense.

Take a container of play-doh, turn it upside down. Does it pour out? Not to my memory. Does it even change shape? Not to my memory. That's the argument that should be used with any power tripping TSO. And as necessary, their lead, STSO, TSM, AFSD, the police, the press, and the OP's Congressman. Letting these TSO power trippers affect our lives is completely unacceptable and only grows their power.

My only other advise to the OP would be to run the item through the x-ray separately from other luggage (i.e., in a gray bin), so that it can be viewed in isolation and so if it attracts attention, that attention doesn't affect other property. There is no need to declare it as a medical liquid/gel/aerosol since it is not, and that will only attract unnecessary attention.