Muslims: explain the whole slave thing?

[Russ]

Assalamu'alaikum'waramatulah.

I was going to a masjid daily and learning Islam for awhile there to really understand it. I wanted to know the truth without the media, ppl, and social media influencing my thoughts. How can i say i know christianity is without a doubt my truth if i dont understand Islam and other religions well? After awhile I just found so many things I didn't like about Islam, but that's just my opinion and no disrespect whatsoever. I actually think Muslims are the most dedicated to their faith then any other religion is. With all that being said, I heard Muhammad ( salallahu alayhi'wassalam ) had slaves. I really have a problem with slavery. I'm an American and I thought what my countrymen did 150 years ago with slavery was 150% wrong. I hate the fact that we had slaves back then and when I hear Muhammad (pbuh) had slaves it really creeps me out. Explain the whole slave process please. Please don't church it up to make it sound better then it is. I want what is actually written about it.
Naw kham I have every right to question what Muhammad did. The Quran does state that every man is equal, doesn't it? That means I'm equal to Muhammad and Jesus as God sees fit. None are better than me or you. Second I have right to question it because if Allah wants me to follow his path, Allah better make it a righteous religion or me and Countless others won't follow the religion.