I don't see anything wrong here, particularly with two other spots free. I much prefer to charge L2 when not on a road trip just to minimize any wear that Supercharging might put on the battery. I'm also not sure But in a scenario like this I'd always check in on Plugshare and leave a messaging offering to move if another EV needs to charge. Now in a scenario where there were Tesla destination chargers available - absolutely, those should always be used first. I previously owned a Leaf and never even thought to be concerned about Teslas parked in an L2 spot where supercharging was also available. I'd consider PHEVs occupying all the spots more annoying, but still a very legitimate use of them.
Also, per Chargepoint.com, it looks like these are free to use. You're suggesting that because I own a Tesla, I should not be allowed to take advantage of free EV charging that is offered to other EV owners? I don't have free supercharging.
OP's point is to be kind. Anyone remember pumping gas? Many stations have only a few diesel pumps built into the gasoline pumps: if driving a gas car, did you try to leave the diesel pumps open and use gasoline-only pumps first? Or not care and block the diesel pump so those drivers would have to wait? It's all about courtesy, except with EV charging the times are increased dramatically.
Absolutely. If there's Tesla destination chargers, Teslas should only be using the Chargepoint has a means of last resort. But I don't see supercharging as equivalent to L2. Now regarding courtesy, absolutely - that's why I'd always offer to move if another car needs to charge to continue on their trip (via a Plugshare post).
In short, I think it is possible to be kind while also L2 charging when there are no other L2 options available. But I don't think that just because Tesla has invested heavily in a paid EV fast charging network that I shouldn't be allowed to take advantage of L2 charging opportunities, particularly when they are offered free to EV owners as a perk of choosing that particular garage. Would a Leaf with ChAdemo not be allowed to charge from a free L2 charger in a lot that also held a paid EVGo or Electrify America ChaDeMo setup? After all, there are Leafs and other EVs on the road that don't have DC fast charging capabilities.