There are 2 critical points leading up to that list:
When the very same GeoHot released a hardware glitch for PS3 OtherOS to let you use more of the system (extra SPU and GPU access rather than software rendering). It should be noted that this was ONLY OtherOS and required soldering. Did Sony really think that people were going to commercialize homebrew games that require hardware mods? Or did they know that GeoHot was onto something big?
As revenge, Sony took away OtherOS for everybody and reassigned Geoff Levand.
And when then GeoHot hacked the 3.21 firmware just to get OtherOS back. Sony blocked it again. This was the point forced the community's hand to looking for solutions that might also allow piracy (although the wheels may have been in motion already). Really, based on the PSP experience they should have known how this works.
Sony sought the right (and won it) to subpoena the IPs of everyone that had done something as viewed GeoHot's blog, watched YouTube, Twitter, donated via Paypal, etc [1].
Sony sought the right (and won) to search all of his computer equipment [2].
These are severely heavy-handed tactics. They wanted to embarrass and persecute him. They took this thing personal first.
And when then GeoHot hacked the 3.21 firmware just to get OtherOS back. Sony blocked it again. This was the point forced the community's hand to looking for solutions that might also allow piracy (although the wheels may have been in motion already). Really, based on the PSP experience they should have known how this works.