Nice work Jakey, you're a corporation's wet dream, willing to forego your consumer rights and adhere to any old vague warranty statement without so much as a whimper. Not only that, you're willing to post on public user forums that you feel this way and advocate unreasonable warranty conditions! Good boy! Roll over! Who wants a tummy rub?
By your reckoning, a device which spends all of it's time strapped to human heads does not need to deal with the completely natural environmental conditions that entails. No, instead the user should remove the device from the head every time moisture is detected on their brow because the device cannot be expected to cope with this. Right. Yes, that's reasonable. How about, here's a crazy thought - if you know that your device is going to be strapped to a human head all of it's active life, maybe try and make sure the device cannot sustain damage just by being where it has to be? Customers should not expect to be charged to repair something resulting from poor design. That fact an HTC HMD can even sustain sweat damage is a fundamental flaw in its design and/or manufacture. The manufacturer should absolutely take responsibility for this and offer free repairs.
Heads sweat. HMDs go on the head. HMDs need to be able to handle sweat.
And comparing this to chucking liquid over a laptop? Did you really do that? Yes, you did. Well done again.