It was intentional hyperbole.
They might not say worm food, but the point is there is very little consideration for the dead with this action.
It doesn't say "Seven with Jesus" If it said that, I would probably be inclined to be on the atheists filing this lawsuit's side.
It says a vague "heaven" which is perfectly fine. "Rest in Peace" or "They're in a better place now" are just nice things we say when discussing the dead even if we don't believe them to be true.
Even Osama Bin Laden, if a Christian said he's burning in hell or an atheist said bacteria is eating away at him, I'd lose respect for that person despite it being true to them. Not cause I miss Bin Laden and want him back, but I think that disrespecting the dead is a horrible social image to portray.