On my land Goatboy I don't need a licence to use many pesticides, or to operate a vehicle come to that - and that's my point. People should have the right to do what they like up to the point that it affects others.
Whilst I am all in favour of freedom to do as one pleases on ones land, and can support the "people should have the right to do what they like up to the point that it affects others", with a chainsaw, if you screw up, it won't be just you it effects.
You have an accident with a chainsaw, and assuming you're fortunate enough to live long enough for someone to make a 999 call, you will have arriving in pretty short order at the very least 2 crew in an ambulance, likely you will also get a paramedic FRU. That's 2, possibly 3 people, who you are putting in danger coming out to provide you with treatment.
(Tangent: I would say that due to the nature of liquids leaching through the environment what you say about pesticides being on your land only, is not really true either, but that is a different topic. )
On the subject of PPE, I do not yet operate a chainsaw, I do however provide labour for a couple of trained chainsaw operators moving logs around, and generally keeping as far from the moving chain as I can. When doing this I wear a petzl helmet. I do this as on several occasions substantial chunks of wood, and even a stone on one incident, flew off the chain, and hit me on the side of the head. My helmet meant that I shrugged it off. The wood chunks would have been an annoying bruise, the stone may have required treatment were it not for the helmet. PPE is there for a reason.
The chainsaw is a deadly tool if not used correctly, and while I do not think that requiring a license for everything is always the right move, where chainsaws are concerned, you cannot be too careful. Do the course, get the PPE, be sensible. If you don't you're putting the members of the blue light services in danger by your own recklessness.
'With chainsaws - as with guns - you can move from "everything's fine" to "life-changing catastrophic failure" in a second.'[1]'
J
[1] In quotes (' ') as it is the direct words of said chainsaw operator.