Noted fringe theorists no one ever heard of Marx and Engels.

I'm sure people have tried to define basic terms like socialism to you because you're politically illiterate. Thats not a scam to "define terms" to win an arguement it is a literal defining of terms, of actual words, that you don't know the meaning of

Don't bother friend. I know from long experience that they will insist on defining the terms of the discussion on their own, as if some whack job fringe theorist is somehow to be accorded the final word in adjudicating our use of language.

Ahh right, why should adherents of an ideology have any say in how that ideology is defined and how terminology specific to that ideology means?

The problem therein is of course that when your opponent gets to set the parameters of meaning and discussion

Your opponents shouldn't get to set the definitions, but the opponents of socialism should get to set the definition of socialism. Makes sense.

you aren't really exchanging ideas on an intellectually even playing field.

Correct, thought the intellectual disparity clearly cleaves in the opposite direction to what you believe.

as if some whack job fringe theorist

Fringe figures like Marx