Why do the supports always get blamed? Is there anything I can do to help a team that doesn't want to be helped?

Currently blessed to be in low-mid plat where everyone is so nice to each other. My games are very hit or miss, where one team is usually piledriving the other. I'd like to think I'm pulling my weight as moira (since no one ever wants to be main healer), usually with 7-8k damage and 12-13k healing per 10 with very few deaths (and most potgs). I've observed that most of my losing teams are comprised of DPS that try their hardest to avoid standing behind shield, or are a story above or below me out of reach. Many times it is only me behind the reinhardt while everyone else is scattered and my other support is more focused on doing damage than healing our very confident solo DPS's. We inevitably lose and the first thing to pop up in chat is "absolutely no heals" "bad support". No one wants to accept their own mistakes and instead they blame us (and yes I've done it too probably). It is SO common for both supports to be dead and have the rest all spamming for heals and then flaming us. It is even more common for my teammates to RUN AWAY FROM ME while wanting heals. Not to cover, but just around another corner to expose themselves. I feel like a mother duck with rebellious ducklings. What can I do in these situations? Is there something wrong on my end if I can't heal a pharah and balls deep doomfist/genji while my reinhardt is being melted?