Just a quick search and you have a statement like this from 2017 from Marinelli before the season started:
"Probably not, not that I can remember,'' Marinelli said entering Sunday night's game against the New York Giants. "But I think part of our system is it's our job to get these men prepared.
"We have no excuses, none as coaches. They reflect us.
If the reflection isn't good, then that's on us.''
Here's Scott Linehan after the Texans' loss when Allen Hurns lashed out about the play-call on an interception:
“I’m the first one, if you had a better play against that coverage, to say we could’ve had a better call there,” Linehan said. “
You can put that more on me. You don’t have to put that on Allen Hurns.”
Here's Garrett when he was coordinator in 2010 taking blame:
Dallas Cowboys offensive coordinator
Jason Garrett is taking the blame for trying an ill-fated play at the end of the first half Sunday against the
Washington Commanders instead of having
Tony Romo take a knee.
"I called the play," Garrett said Wednesday. "
It's my fault."
I could keep going, but hopefully this will suffice.
Coaches, especially coordinators, taking blame when their unit isn't playing well is perfectly normal. Fans are reading way too much into this.