Why is 'Honi Soit Qui Mal Y Pense' on the UK Monarch's Coat of Arms?

Good Morning, RP Family. Last night, I did a post-review of my postings an observed members calling each other "evil". My only civility warning is "honi soit qui mal y pense."

Pronunciation - https://www.merriam-webster.com/dictionary/honi%20soit%20qui%20mal%20y%20pense

Please remember that the mind is a terror-able thing to waste.