It's similar to the whole "Thanks Obama" meme from years ago.
Basically it's "Ted Cruz is why <insert first world problem or minor annoyance here>". The idea is to make a joke out of people seemingly blaming him for the weather and everything else they can think of.
Some zingers include...
-Ted Cruz is why your daughter is dating that weird kid from her art class.
-Ted Cruz is why your check engine light never turns off.
-Ted Cruz is why the McRib isn't a permanent item on the menu.
Go ahead, try it out in a random thread about Cruz!
Ted cruz is why your {gender identity} kid got sent to Mike "deus volt" prices therapy centre?