"The nature of Bitcoin requires users to run fully validating nodes, necessarily involving downloading, storing, and transmitting every transaction, even if they are fake/spam "transactions"."

"downloading, storing and transmittting every transaction" - this is untrue.

"downloading and validating" - this would be true.

utreexod is an example of a fully validating node that downloads and validates but does not cache (store) and need not retransmit every transaction.