Yeah I am with you. Not for this - if it was only this it would be petty. But it wasn't only this seems like even the little you have told is the tip of the iceberg. Just because they are old friends doesn't make them good friends. 

But you don't feel good about it or it's caused problems at the table or you don't feel good about the reaction, or you wouldn't have started this topic, right?  People don't usually make this sort of external appeal unless there's some sort of judgment or condition at a local level causing distress or dissatisfaction (though, this is very much a moot court for anything other than validation purposes).

I, you may have noted, was one of the ones who pointed to the financial overhead you provide your game as part of your grounds for grievance.  You felt injured in that your property was being misused or abused by players in your campaign.  And everyone I believe can appreciate, value that feeling.  

You aired your feeling on discord, something which all your players "can see".  How busy are there discords.  Did you receive any feedback when you issued this notice, at minimum an acknowledgment as small as an "ok" from anyone.  If not, you posted, but you can't be positive the message was received, and would contribute to the feeling that may be held by the offending players that your deletion remedy came out of no where.  You say you then "mentioned" it at the table.  Did the offending players acknowledge the message?  If not, did you just let it go.

Regardless of the reception or lack of reception of the warnings, when you deleted the characters, how did you think the players would react?  Think of the art gallery analogy I presented, you destroyed what they thought of as their work (yes wrongfully produced within your virtual gamespace and therefore literally at your disposal).  The fact that this thread exists suggests you didn't anticipate what would be a likely response, if not the most likely.

So, you got hurt, in your assertion of control over your property, you hurt them.  What are your options now.  As I wrote before, you can entrench yourself in your justification and let the others resentment fester or maybe they'll suddenly mature and let go of their slighted feelings and just move on and game on at your or another table.  My advice is to constructively clear the air.  In front of the group or just with the offending players tell them how you felt injured because of the other players use of your game resources outside of your game.  Then make the brave move and accept that your decision to delete the characters hurt the feelings of the other players.  Then you open the discussion by asking "How do we make this right?"  Ideally you'll get an admission that they were taking advantage of you, or now recognize that and an apology.  In turn you can apologize for nuking their characters.  Then structure a way where you can all go forward in the group maybe by only using your resources for your games only or maybe subsidizing your overhead as a means to allow them to use your tools as a workshop for other games they're in.  

Or you could stand by the voices saying you had to lay down the law. That is a justification.  I will say as someone with substantial experience in much higher stakes situations of conflict and crisis intervention and negotiation (who did have pretty broad authority to "lay down the law" smackdown style if I thought the situation was going south), you're probably not going to feel good about it for a while.  Eventually you'll get over it, but the initial injury will just callous you and the subsequent injury will callous the other players.  It's a scar.  What I've propose is more restorative and will generate better faith in the game going forward.  Up to you.  On any real value level, we're talking a literally petty dispute (how much bandwidth did the offending characters literally cost you?) so I won't even charge my high stakes intervention rate.  

The discord channel is literally that group of 6, my wife, myself and 3 other people. It's not a busy discord.

Regardless, we cleared the air last night. They apologized. They also know I am moving across country in a few months and they won't have access to all this stuff anymore, anyway.

Pretty sure no-one who's posted on this forum is fully on the side of your players and no-ones missed how much your giving to the other players. 

All seem to agree that you have a right to feel angry and used, but a few are pointing out that there were much better options that were available to you. (and far quicker, seriously you could have de-activated the campaign and told them to rejoin a new one with active characters only)  I think by coming on here you know that it came from a place of anger and don't like to see that in yourself. (Even if it is justified)

I would like to state that I am not condemning your actions and agree with the general consensus that your players have far more to apologise for, I was just pointing out that at-least the level 11 player lost more than free access to content.

Agreed.

But the owner of the 11th level character just revealed that he has a Master Sub and all the content, and has now told everyone that he is content sharing as well. So he was just using it as a convenient option.

Regardless, it's over. Everyone has apologized and they now realize they will no longer have access when I move, because they won't be my group anymore. 

It was an angry, petty move on my part, but it was also a selfish move on their part. We all get that and we all have moved on.