Earlier quoted context omitted.
Not in my experience. The devs in teams I've worked with (including me) are most of time all quiete aware of the places where their code en setup is lacking and as long as they don't feel personally attacked are very happy with people who come with implementable solutions. The not feeling attacked and implementable parts are key.
This. I've never had a negative response when I joined a project and discovered obvious problems when I explained why I think that they are or are going to be a problem and offered to help fix them. Nobody likes the guy that shows up, says "that's all shit, you need to fix it", and vanishes again. But I've never seen anyone hate the guy that shows up, says "I've noticed there's a lot of friction around X. I think we…
But I've seen people giving negative responses to the best feedback. Hell, I've had people complaining for hours because someone else replaced their manual process that took an hour to do with a script (and copy&paste of the result) that took literally seconds to run.