I personally don't see anything wrong with the invitation. He just sent an invitation to the community. I don't see it an agenda to promote his event. Removing him from the list will be an unfair judgement.

On Aug 19, 2015 8:30 AM, Nkansah Rexford <nkansahrexford@gmail.com> wrote:
>
> Quarshie Timothy posted a similar message (via eventbrite) in about 2 months ago
>
> https://lists.wikimedia.org/pipermail/wikimedia-gh/2015-June/002712.html
>
> It'll be best caution begins with action now.
>
> On Wednesday, August 19, 2015, Felix Nartey <flixtey@gmail.com> wrote:
>>
>> Rexford i don't think we should rush in removing anyone from the list now. I believe we have all learnt from Michael's mistake and w'll hope it doesn't happen again.
>>
>> So the caution i presume will take place in the future.
>>
>>
>> On Wed, Aug 19, 2015 at 8:01 AM, Nkansah Rexford <nkansahrexford@gmail.com> wrote:
>>>
>>> Asaf: These are making it through because senders are part of the list. These are not messages from non-list-members.
>>>
>>> All: Any kind of these type of promotional messages comes through the list, the user will be deleted without any further discussion, beginning with Michael Mettle-Nunoo.
>>>
>>> Thanks
>>>
>>> On Wednesday, August 19, 2015, Asaf Bartov <abartov@wikimedia.org> wrote:
>>>>
>>>> List admins: why are these things making it onto the list?
>>>>
>>>>    A.
>>>>
>>>> On Tue, Aug 18, 2015 at 9:43 PM, Michael Mettle-Nunoo <niimichaelk@gmail.com> wrote:
>>>>>
>>>>> The Official Launch of Mazzuma
>>>>> View this email in your browser
>>>>> <table style="border-collapse:collapse" width="1</blockquote></div>