Hey, sorry for being off-topic, but the rule as listed under the The Basic Rule section of your webpage does get hit. This one:
❌ /ip firewall filter
❌ add action=accept chain=forward \
❌ dst-port=22 protocol=tcp \
❌ in-interface-list=WAN
(assuming the forward chain of the filter table has no other rules before that one).
That rule is part of the #14 box of this flowchart. Your statement is only correct for the case of chain=input (#7 in the flowchart).