Putting people at ease around you (especially customers) is a critical entrepreneurial skill.
You can't blame people for being cautious when a lot of people are buying into victim-narratives and convinced to act against their "oppressors".
I do not exaggerate when I say that the amount of meaningful advice I've been given since I adopted this technique has increased 5x.
Another perk--due to my vocal policy on this, I had an autistic colleague tell me that I'm the only woman he feels comfortable working with. He struggles to read social situations, and he frets that women will interpret his bluntness as him being dismissive or "mansplaining." It made me very sad to think he's missing out on good relationships with so many talented women in our office, just because of this environment of fear. But he's a wonderful friend and colleague, and I am so happy to have his advice and support.
It's sad, and sometimes frustrating, that I have to think in these "nuclear arms race" terms. And that's something else I try to be open about: that I'm really frustrated with this environment of fear. I think the more people openly acknowledge that, the easier it will be to move toward a healthier environment.
Why is that more important for cybersecurity teams? Is it that other teams can sometimes look at security as something annoying that slows them down? So they care about security not because they care about security, but because you + team are their friends? :-)
It's also very common for people to view cybersecurity engineers as people who needlessly make things more difficult just so they can "look like they're busy" and collect a heftier salary. (I've found this mindset especially common in non-technical teams.)
We're kind of like the dentists of the industry--everyone grumbles about how pricey we are, no one looks forward to visits from us, people question whether we're actually fixing things or just out to make a buck, and we have to hand out all sorts of annoying reminders (floss your teeth! don't install Chrome add-ons! brush twice a day!)
Having a strong relationship with other teams allows me to come to the table and say, "Hey, look, we both respect each other. You know I don't bullshit, and I wouldn't be asking you to do this if it wasn't a real issue. So please at least listen to my concern and try to work with me here. And you know I'll always listen to your concerns in turn, so we can do this as painlessly as possible."
So it's not exactly "getting them to care about security because we're friends." It's more of, "getting them to listen because we both respect each other." And if you can do that--get them to listen instead of having them immediately shut down, get angry, and convince themselves it's all bullshit--then usually they'll quickly understand there's an actual threat at hand. And once you convince them there's an actual threat, they're way more likely to do something about it, instead of throwing a fit and resorting to vindictive pushback.