No, you are and can.
You just have to keep the above copyright and permissions notice in your distro somewhere visible by end user.
Doing that actually is giving credit to from who come the source used in your, closed source, distro.
Modifications made by you don't have to be open sourced, but the license requirement make at least sure your end-users can discover from where comes the unmodified source.
Please note that the use of "Haiku" trademark is a different thing, and comes with its own requirements.
But you perfectly can do a closed source distro of you own using the MIT licensed source from Haiku project until you include the copyright and permissions notice. And conform with the parts that are licensed under more restristive terms (or don't use it).