Selling capes - or rather, in this case, making money off the modpack (via CF) which includes capes - is a violation of the Minecraft EULA.

"sell cosmetic entitlements, except for "Capes," which we define as anything that attempts to visually emulate the feature of a Minecraft player Cape."

So this should probably be removed since violating the EULA is, well, violating the EULA.

I do not agree.
I actively suggest people to obtain free capes, while also giving the options to use the capes they already paid for elsewhere. If there is any problem with this, it should be communicated with the cape providers, not me.

Edit: added a disclaimer to https://fabulously-optimized.gitbook.io/modpack/readme/free-cape