We have an organization called 'National Association for the Advancement of Colored People. NCAAP for short.

I think "colored" was the common term used at the time of the founding of the NAACP. 

The common terms now are Black or African-American and that is what we should use. 

I think if you use a term after someone tells you they do not like to be referred to by that term then yes...you are offending them.