This is a tricky one...the fact is that the use of cameras in France is very stricly monitored (way more than in most countries) and Disney are right to say that they cannot give details of where they have their cameras. I mean, no company would give that info, so it is unreasonable to expect Disney to do the same. And if even the Police admit that there is nothing they can do, then it is difficult for Disney to prove otherwise. The problem is that: proof. And this is where Disney are in the right, as their system cannot find any fault with the door (and neither can the Police).
Personally, despite what has happened, which is dreadful and I am not condoning these actions, it is difficult to engage the legal responsability of DLRP and I believe that your case has been passed on to senior management...I mean, what you say is serious and such matters are always followed up. As the Hotels are accessible from the outside (in the sense that anybody can reach reception, which is entirely normal everywhere in the world), then I guess that we do have to go along with the "other Guest action" spiel, because there is no proof otherwise. As noted above, there is the problem again...proof!
I do think that your experience is awful, and I can only hope that nobody has to suffer anything like that, but it is difficult to hold anything against Disney in such cases. I work as a lawyer in Paris and honestly, the French legal system makes it really tough to prove this sort of attack. Perhaps the system is wrong, but the problem is that without proof, you cannot pursue this in any way. In addition, and this is just personal advice, I would be wary of printing the whole reply from Disney on these sites: the CMs have a right to privacy and by printing their names, you run the risk of being sued yourself. Be careful, that's all I am saying, but I would recommend taking out the names of the CMs who wrote to you- after all they are doing a job too and it is unfair to cite them. This is also why Disney always put "Private & Confidential" on every letter, as it keeps them safe (I notice you 'forgot' to print that bit).
Seriously, you had real bad luck and I am sorry for that. But Disney cannot do anything in this case, and I would be wary of accusations on websites, especially where Disney are (legally) "in the right".
Visit again, one bad experience should not put you off for ever, and tough though it may be to understand, this sort of thing can happen worldwide and is outwith the direct control of Disney (partly due to the French legal restrictions).