I suppose technically they are correct.

If people with compromised immune systems mix with people who have a healthy immune system, then there is clearly a risk to the immuno-compromised.

It's what they don't say that's important here.

For example..

• Unvaccinated people don't pose an increased risk to other unvaccinated people
• Vaccinated people pose an increased risk to other vaccinated people
• Vaccinated people pose an increased risk to the mental well-being and calm of unvaccinated people