Since you seem genuinely confused I will elaborate.
You are comparing 2 completely different things here. Android is a free platform. Sony has noithing to do with this other than putting it on their hardware. Apps for Android are approved by Google only with no say for Sony whatsoever. Vita on the other hand is Sony's property and as such monitored by them. There are only a handful of apps on the Vita and all of them are Sony approved. Apps have to be Sony approved and they won't let an emulator on it due to technical, economic and legal reasons.
Secondly you need roms for the emulator. Where will you get those roms? Definitely not from a Nintendo approved channel. Therefore all of the roms aqcuired are illegal. Nintendo is one of the most strict publishers in this world when it comes to their content. They have to have full control over everything or else they will sue.
Now you tell me why anyone would even start to try getting an app out on the vita which is borderline illegal and hurtful to both companies involved?
If you demand respect or gratitude for your volunteer work, you're doing volunteering wrong.
