Spam defenders will often point to the fact that a spam transaction is valid, in the eyes of the protocol, because it pays the required fee and respects the structure required by the protocol. Even though the transactor paid a fee, it does not mean that the transaction cannot be a spam transaction. By definition, spam will always be a valid transaction, it would otherwise not be relayed through mempools and won't be included in a block. That does not mean that some valid transactions are not violating the two definitions previously defined, meaning that the transaction can still waste the shared resources of the network and/or abuse one of Bitcoin's functions for a malicious intent.
Discussing the validity of the transaction is not the issue and participants should not let the debate diverge in that direction. Spam will always be valid, the questions that should be discussed are:
● Are these transactions willingly wasting the shared resources of the network?● Is there a malicious intent behind this wave of transactions?● Can the purpose of these transactions be achieved more efficiently?● Are these transactions abusing some of Bitcoin's functions to circumvent limitations put in place to preserve the network's resources?
Another important detail is that some of the spam from the current wave, mostly inscription-based spam, can be considered to not be paying a fair fee as it circumvents the fair fee market by injecting data into the segregated witness space in order to benefit from a x0.25 discount. This is not the case for bare multisig based spam or OP_RETURN based spam.