This is tricky myth statement! If you thought this was true, it is perfectly understandable.
Attitude and behaviour are very tricky and delicate subjects to address within a team. If there are problems with these subjects, a lot of times they are not addressed openly.
One of the reasons for this, is team members who are bothered by these problems have a hard time stepping forwards because the problems are most likely very confrontational to others. Next to that, team members might lack the skills or confidence to be able to do this in a constructive and non-threatening way.
There might also be the tendency or belief that these things are best addressed by someone outside (or more on the outsides) of the team, so it can be more neutral.
As a Scrum Master, you should be aware if any factor that might inhibit team members to speak about behaviour and attitude openly. As a Scrum Master your primary concern is to coach the team on this and to establish and strengthen the concepts of Trust and Openness.
Only when these are strongly en naturally present within the team, behaviour and attitude can be freely discussed.
Because, as Scrum Master, you are the natural coach and guardian of the Inspect, Adapt and Improve processes, the rest of the team might (maybe even unknowingly) expect you to take the lead in this as well.
If the Scrum Master feels comfortable to address these topics, there might also be a natural tendency to take the lead in this.
Even if Trust and Openness are abundant, team members might still need examples on how to tackle these delicate topics. Because with Trust, skills might still be lacking. Leading by example is one of the tools of the Scrum Master, so in essence there should not be a problem. The implicit problem might be if the Scrum Master steps in on his or her own initiative, instead of being asked to do so. It deprives the team members of exploring on their own. taking more of a mediator approach could be more insightful for the team.
So, the Scrum Master has a choice:
1. address behaviour and attitude problems as Scrum Master,
2. lead by example, consciously taking the team on this learning experience
3. let the team address the problems and be an active mediator and gatekeeper
4. let the team address the problems
These are more or less stages, which can be seen as levels of “maturity”. Which does not at all mean that level 1 is immature!
As Scrum Master, you should be aware of what stage the team is roughly at, and take position accordingly. In practise, this can be hard, and demands constant reflection. And maybe even actively pushing back on urges. And in the first three stages, the Scrum Master has en active role.
Therefore it might be logical for the Scrum Master to address these kind of problems. You might see this happening a lot. In the end, the Scrum master is the impediment resolver, and therefore, if the team is really unable to address the situation themselves, it is the Scrum Master to eventually step in. In whichever way is necessary. The challenge for the Scrum Master is to find the balance in when to step in and when not to. And what tools to apply, how to coach etc. In a perfect world, the team addresses behaviour and attitude amongst themselves, but the Scrum master is the constant available backup. So it’s a myth that the Scrum Master is the one to address, but it is not black and white!