Even the gospel is possibly compromised in a couple of the details. I've seen a couple places that are sus. However, the deeper message, the teachings are very likely largely untouched. Such opportunism fits their MO.

In their division tactics they create one side that is mostly false, to oppose the one side that is mostly true. They tweak the false with just enough truth and reasonable philosophy to keep the believers believing. They take what's true and tweak it just enough to keep the people that side with the true unwilling to look at the ones creating the division, causing them to stay focused on the "false side" as the only enemy.

They maybe also throw one or two falsehoods in to dull some of the finer points, or create justification of doubt so that the false side stays on the false side.

Its insidious but you can see such tactics throughout history. It is obvious in our Dem. v. Rep. battle, but its everywhere once you realize it. I see it in every religion v. religion, or every parliament, every social ethics struggle, economic struggle, every single place you can see such tactics. Its almost the definition of what it means to be socially divided.

Its pretty fascinating.