[wvenable]

hobby /ˈhäbē/

    1. an activity done regularly in one's leisure time for pleasure.

If you enjoy the activity then it is neither pointless nor a waste of time since the primary purpose is enjoyment. If you don't enjoy it, it's not a hobby.

No doubt these posts could be your hobby; you do it for pleasure but it's otherwise just a pointless waste of time.

[sandblast]

Hedonism — the doctrine that pleasure or happiness is the sole or chief good in life.

"It's not a waste of time since the primary purpose is enjoyment" — in that sentence you place enjoyment above any other benefits the activity might have (but most often does not). Hence, it's a hedonistic approach.

[wvenable]

I was not making a global claim about ethics; I was defining what makes an activity a hobby. Saying "for hobbies the primary purpose is enjoyment" doesn't assert that pleasure is the sole good in life -- it simply notes the internal aim of leisure activities done for their own sake. That aim can coexist with other goods (skill, friendship, health, meaning) and the fact an activity fulfills its own goal means the time isn't "wasted" even if no external output results.

Enjoyment here is a sufficient justifier within that domain, not in a life-wide philosophy. Labelling it "hedonism" is a significant overreach.