The variable in question is placing a limit on OP_RETURN data. Ordinals do not use OP_RETURN data; they put their data within the witness.
many valid transactions use opcodes(subclass: sigops) that have actual validation conditions of requiring signatures in witness of a certain format that meets most updated policy
ordinals junk use opcodes that dont look for specific conditions and just treats as valid without checking content
code can be used to recognise someone using the unconditional opcodes and set expectations of extreme fees if people use opcodes without the conditions of actual signing proof validations