You’re a support player, so this will resonate with you.
You can see where everyone is. Where everyone needs healing. You can see which routes they are taking more damage from. You can see when someone dies because of their poor positioning. You can see when someone takes too much damage because they took a poor route. As a support player you’re in the back and you “SEE” more of the game than you’re average DPS player. The information you have about how your team is taking damage and from where is unique to a healer.
As support with the information you have you have several goals. Your goal should be being aware of your own positioning, the position of your team relative to your healing, and the teams position relative to the damage output. As a support it is well within your right to call out someone for dying consistently due to their poor positioning, map awareness, or mismanagement of their cooldowns. A D.va who pops D-Matrix into Zarya and Mei? You can 100% call them out on that.
Just as a Tank or DPS player who is trying to peel dive off of you can call you out for either a) not calling the dive out, or b) being out of position yourself to cause the dive.
Thats the thing about a team game. You HAVE to take into account the calls of your team and then use your own best judgement to then adjust your play style. If you’re entire team calls you out on your positioning maybe you need to look at where you stand and not scream and cry that the meanie heads are being toxic.
TL;DR 9/10 times the people you play with know more about you play than you give them credit because they are watching you play from outside your tunnel vision.