Before deciding to enter a new market, serious firms do a PESTEL analysis. Twitter must have done that too.

Political: how politically stable is Nigeria compared to Ghana?
Economic: Would you want to invest in Nigeria, with its crazy monetary policies, high inflation etc.

Socio-Cultural: Is a hypocritically conservative society like Nigeria with serious ethno-religious strife, the best location for a social media network?
Technological: Nigeria probably beats Ghana here, but other factors count against Nigeria.
Environmental: Not relevant here.

Legal/Regulatory: This is where Ghana beats Nigeria hands down. Regulations impacting on technology/fintech in Nigeria are often arbitrary, and counter-productive. No sensible person would want to invest in technology here - not after the experience of Gokada etc.

So please understand that Twitter did not decide to invest in Ghana over Nigeria simply because "Nigerians have a nasty habit of de-marketing Nigeria through their tweets".

That isn't how any serious business makes investment decisions.