madness really

Hello everyone. I would like to know what "madness really" means in the following sentences:

‘Tell them to be really careful with this. It could give you a nick from the slightest touch. The bride asked for it to be sharpened specially – , as a knife like this is really meant for cutting through meat. It’ll go through that sponge like it’s butter.’

- Lucy Foley, The Guest List, Chapter 52

This is a thriller novel published in 2020 in the United Kingdom. One hundred and fifty guests gathered at some remote and deserted fictional islet called Inis an Amplóra off the coast of the island of Ireland to celebrate the wedding between Jules (a self-made woman running an online magazine called The Download) and Will (a celebrity appearing in a TV show program called Survive the Night). Here, during the party after the wedding ceremony, the wedding planner Aoife and her husband Freddy are preparing the cutting of the cake.

In this part, I am wondering what "madness really" means.
Would that perhaps mean that asking for the knife to be sharpened especially was madness (crazy, or unbelievable) because the knife itself was originally made for cutting meat, and didn't need to be sharpened to cut the cake...?

In that case, would it be okay to understand that "it is" is omitted before "madness really," as "[it is] madness really"? Or perhaps, would it be "[which is] madness really"?

I would very much appreciate your help. 👁 Smile :)

It means that this was an unwise or foolish act.

Tea Addict said:

Would that perhaps mean that asking for the knife to be sharpened especially was madness (crazy, or unbelievable) because the knife itself was originally made for cutting meat, and didn't need to be sharpened to cut the cake...?

Yes. "Madness" does not really refer to mental instability, but to recklessness or being excessive.

Tea Addict said:

In that case, would it be okay to understand that "it is" is omitted before "madness really," as "[it is] madness really"? Or perhaps, would it be "[which is] madness really"?

It probably doesn't make much difference, nor whether you use "is" or "was" (unless an accident has already occurred, when you would need "was"), but reading it as "it is" is easier. "It" is her asking the knife to be specially sharpened.

A knife used to cut cake doesn't need to be sharp, let alone extra sharp. They even make knives for cake cutting out of plastic.

Dear S1m0n, Uncle Jack and kentix,

Thank you so much for the explanations.
So "madness really" here means that the bride's asking for the blade to be especially sharpened was excessive, unwise, and foolish, especially when the blade is already sharp and can be used for cutting meat.
And it would be okay to think that "it is" is omitted before "madness really," "it" being the bride's asking for the blade to be sharpened.
I truly appreciate your help, as always. 👁 Smile :)