ssd
Those posters are ridiculing families who are struggling with their mental health.
They are trying to be oh so clever and cool 
. The 'joke' is that parents who decided it was safer to wash and isolate their shopping in March 2020 are so ridiculously and unreasonably anxious themselves that they have passed on their own anxious behaviours to their offspring. It's victim blaming.
It's a cruel and simplistic comment, basically.
Some parents struggle with anxiety and might indeed pass their anxieties or worries on to their dc. However this is no laughing matter and actually one of the very important reasons why schools need to remain open so that when families aren't coping very well the dc continue to mix with people outside of their families, get an education and build their resilience and also get respite from a difficult home situation.
In many cases, however, children have developed anxiety and or depression without their parents having been overly worried about Covid. Children who are naturally extrovert will have struggled more during lockdown. Children who have had to repeatedly SI to protect their community and missed out on education, exercise and socialising with their peers for long periods as a result will be affected by this, of course.
Dc from homes where both parents work in demanding jobs might have picked up in their parents stresses. Those who have had to do this know that supervising 3 young children with their online school work while being stuck on back to back video calls is incredibly stressful.
But yes, 'let's make fun of people who worry about their kids' mental health, it's so very funny. No it's not, it's a painful, lonely and hair raising experience when dc display anxious or depressive behaviours whether it is brought about by your own fragilities or simply as a result of the Covid pandemic. 