Struggling to work out if I am being unreasonable in my reaction to this.
Have an ok relationship with my MIL, not amazing but I don't see her all that often and when I do it's cordial. Even my DH will acknowledge that she can be quite a selfish person, will love to talk about her own illnesses etc but won't notice if your own leg is about to fall off in front of her. He assures me that she does like me but I do often find her quite dismissive of me and she will often do things like looking directly at another person while answering a question I've asked her, or not immediately or at all respond to me if I pop my head in on Skype to say hello to her. Anyway, not malicious my husband assures me - just part of her slightly self-centred ways.
She is due to have an operation next month that we hoped to be around a bit afterwards for, to help her and even frailer FIL manage while she recouperated a bit. However now that the dates come through for the op it turns out that it coincides with us being out of the country to visit some of my relatives and we won't be around. Felt a bit bad so I asked my husband if I should send her a nice email suggesting seeing her before we travel and apologising that we couldn't be around more when she needed us. I wrote to her, apologising profusely that the timing had turned out badly, suggested a date we visit them before we go and take them out for a nice meal and then go with the children to a petting zoo near their house. This is not an inconsiderable effort on our part, it's a two hour trip each way and we have two small children but we're happy to do it. Now the AIBU part... the response to my email came last night, but what's annoyed me is that it's not actually a reply to me at all. She has cc'd in all of my hubsbands siblings, several extended family members and some of her and FIL's friends to the reply. She has not acknowledged in any way that she's responding to my email, i.e. the greeting doesn't address me, it just says hi, there is no acknowledgment of my apology for not being around or if my suggestion to take them out for a meal or do something nice with the DGC. She has basically used my private email as a public platform to discuss her operation and thank all of the people who will be around to help them. It could be a completely stand alone email, except for the fact that my private email to her is tacked to the bottom for all to see. The only slight indication that she has even read my email is a comment to my husband that on the date I suggested visiting that there is some DIY they need doing around the house so can he bring some tools. I have been so cross since i read it, I just think it's unbelievably rude. But my husband thinks I should just let it wash over me, no big deal and just his DM being slightly thoughtless. So AIBU to still be so angry with her?