Why isn't the word for "windsurfing" an infinitive verb?
When you want to actually do it, then it is. Je vais faire de la planche à voile. Faire is very versatile like this. Exercise: faire du sport; Paddleboarding: faire du SUP, kayaking: faire du kayak, etc.
So does the sentence literally mean "he only talks about sailboards"?
I thought that a verb was required - il ne parle que de faire de la planche à voile. But marked incorrect.
I think a literal translation for that would need to be plural, since the English (sailboards) is plural:
"il ne parle que de planches à voile"
Il parle seulement de la planche à voile also accepted