So my questions are –
Is this type of Facebook event invite something that others may find intrusive too? Is it because the event is connected to one’s religion and one’s participation in that religious organization?
Annoying but not intrusive. I used to receive FB event invites from someone in another state. I would never attend those. He just sent them to everyone with no regard to the location of the indiviiual he sent them to. I found that rude; i unfriended him eventually.
As others said SIL may have sent the invite to "all" church folks, not singling out DD.
One other thing that comes to mind is perhaps SIL thought there may be a small chance DD would attend but not actually physically participate, just kind of hang out (& be a spectator) for the sake of being with family & friends. I have done so, & would do that again.
I don't feel that the religion connection has anything to do w/ this whether an invite on FB is intrusive.
Is this acceptable in today’s more electronically social world?
I am not sure what you mean by the word "this" exactly? Church FB invites? Or all FB invites? If so, maybe, but only to the people on FB. Not everyone is one FB so those folks are spared the annoying or "intrusive" invites.
Would SIL have been better served to post a reminder of the event on her own Facebook page with just a personal note to say hope to see you all at the event instead of forwarding the event invite asking for a response.
It depends on the SIL's role in the event. If she's an attendee only, yes; if she's heading up the event, then she may - based on past experience- have found the need to generate a FB invite to garner more attendance. It depends on the particular event crowd too... The Youth group is far more likely to respond via FB than someone who is less-electronically dependent (trying not to step on toes, I'm thinking of people who don't have the Internet or a computer at all.)
It sounds like your DDs reaction is a symptom of a bigger issue in her rel@tionship w/her SIL. If she can take the emotion out of it, she may find it a harmless act on SIL's part. Think of it this way. Had the invite been sent by someone else in the congregation who knew all the various factors of heslth issues, timing, etc, would DD have reacted the same?