I'm just an ordinary bloke from a working class background that's invested in Hive over the last nearly four years because I believe in decentralised social media.
I like the fact that rather than one central authority controlling the servers ('nodes') that keep Hive functioning we have over a hundred servers on a 'blockchain' that run Hive in consensus.
The Top 20 Witnesses take on the bulk of the work and eah one confirms ONE BLOCK of data once a minute on average (roughly) -it's quite easy to work out as we have 3 second blocks on Hive.
Each of the T20 witnesses earns around 10K Hive a month, or 120K Hive a year, and given that Hive's been around for a year, that's around the amount they've earned since Hive's creation. The stats below are from 
In fact MOST of these T20 witnesses have been T20 for longer than a year, many have been T20 from at least near the very beginning of that pre-Hive blockchain, so would have earned hundreds of thousands of dollars in block rewards, but at the very least 120K Hive or around $70K for the last year at current prices is a minimum.
Since these T20 Witnesses are the guys who secure the network they are pretty crucial, so I don't mind them getting a decent pay-out, but I also kind of expect some of that Hive to get re-invested - it's like putting your money where your node is, betting on the network you secure to be successful by powering up, and by powering up also better protecting that network from another take over.
When I see a high earning T20 witness on constant PD, selling the bulk of their Hive earnings, I see it the same as an executive selling all their share options in their company - personally I'd have more trust in a witness/ executive who had a larger exposure to their own product.
It's pretty basic really.
I recently unvoted ALL T20 witnesses who have less stake than me
With the T20 witnesses having earned SO MUCH HIVE over the last year or four I've simply trawled through and unvoted all of those who I had voted for who have less Hive Power than me - because I'm just an ordinary bloke with much lower earnings.
There is simply no way I'm putting my faith in a witness who is less committed to Hive than I am.
This is why All the T20 Witnesses I vote for have more Hive Power than I Do. NB some of them may appear to have low HP on their personal accounts but have significant amounts delegated or Powered Up to their projects - like 
I also made an exception for PeakD as I like that application, it is so fundamental to Hive atm unless/ until we move away from the main chain being a blogging thing.
I'm not going to name those I unvoted as it's easy enough to track through the witnesses here and find out who has been selling in droves.
Am I being unreasonable?
Maybe it costs $60K a year to run a node, I don't know, maybe it takes THAT MUCH technical knowledge to be a top witness?
NB I don't generally vote for people who I see selling ALL their Hive or LEO, so I do apply this principle to all actors.
Or is my 72K HP minimum requirement too low for a witness?
Oh I'm aware I'm being a little crude just using raw HP as a measure, because some witnesses would have ninja mined that, but honestly, most of them have had enough time to Power Up significant stakes even without that.
And the rest of my witnesses?
Given that all witnesses outside of the T20 earn significantly less I'm happy to leave my votes on most of them, although I did just unvote one as i noticed TOO MUCH selling going on.
Final Thoughts
Of course every actor on Hive is free to do what they want with their stake, but I just have a higher level of expectation from the higher earners - I expect a certain level of Vest in the product you're helping to power, otherwise I won't support you, doing so just undermines my investment if all you are doing is selling off the 120K Hive you earn every year.