it's a reference to this yard sign, which is popular in the USA: https://www.vispronet.com/in-this-house-we-believe-yard-sign
Discussion
I can put one similar as well but it will state:
all lives matter
protect human rights (men and women are humans)
no human is illegal on planet Earth (but different countries have different citizens and not every one is citizen of every country)
science is real when its not faked
love is love (adults ony if its more than love ...)
true kindness is everything