so one can argue that "which" may refer to "dumbing down of the language" rather than just "language" in A,B and C and that would be ok so ı believe which is not a crucial deciding point here. Also in D and E it may refer to "dumbing down of the language" so, again, it may not be a crucial deciding point.
A) which they liken to making particular crimes legal just because people had committed those crimes
why would use "had committed" instead of just "committed" we don't have different past actions following each other
B) which they liken to, just because people are committing particular crimes, making those crimes legal
ı don't it that it is nice to put an entire phrase in the middle of a sentence, cutting the connection of verb and object
C) which they liken to particular crimes being made legal just because people are committing those crimes
Meaning error, purists don't liken it to crimes; however they liken it to the action of making crimes legal
D) likening it to, just because people are committing particular crimes, making those crimes legal
ı don't it that it is nice to put an entire phrase in the middle of a sentence, cutting the connection of verb and object
E) likening it to making particular crimes legal just because people are committing those crimes
Correct