Wow, this is definitely more a problem with your 'friends' than the app. You should deal with them if they're hassling you rather than just hide away from the problem and ignore it. read receipts are good as you know the person has got the message. the amount of times where i have sent the message and it hasn't actually gone through on FB, despite it looking like it from my end, means this is a good thing.
That is silly. This is an issue for people with business relationships, people with just acquantence familiarity etc.
I don't tie my life to technology. If someone wants to send me a message fine, but I will return it when I choose to and without the implied expectation. Someone is being ignored.
If you have so many problems with messages getting lost that you require a mandatory read reciept you should investigate some more reliable messaging options.
You should not let others puppeteer your life simply by when they choose to contact you. 99.9999999999999999999999999999999% of Facebook messages don't have any sort of urgency or import attached where a read receipt is required.
Having read receipts is not bad, having them not defaulted to off and toggled means your messenger app is entirely broken.