Not exactly.  I'm saying is that since you hold US citizenship (despite
the fact that you also hold Canadian citizenship), you shouldn't be
attempting to enter the US as anything other than a US citizen nor
should you present a non-US passport at a US port of entry.  There's
nothing against you also having a Canadian passport or using that
passport outside the US.  The US simply requires all US citizens to
present a US passport when entering the country (or to present other
documentation that proves US citizenship, when a passport is not
absolutely required - like when entering the US from Canada).

Below is a link to where the requirement exists in the US Code.  Check
section B.

http://www.law.cornell.edu/uscode/html/uscode08/usc_sec_08_00001185----000-.html

I hold both US and Canadian passports, and I live in Canada.  When
entering the US, I identify myself as a US citizen and present only my
US passport.  Conversely, when entering Canada I identify myself as a
Canadian citizen and present only my Canadian passport.  I'm not trying
to hide the fact that I hold the other citizenship from either country,
by doing this.  My US citizenship entitles me to enter the US, so I
just present the document the proves it, as required by US law.  US
Immigration has sometimes asked me, what immigration status do I hold
in Canada.  I've always honestly replied that I'm also a Canadian
citizen, and never had any problem with that.  But I don't tell them
that unless they ask me.

It's totally up to you as to whether you want to continue to enter the
US as a Canadian.  I'm simply telling you what the law says.

Here's another website - it's written by a dual US/Canadian and has a
lot of good information if you're interested.

Cheers,

Stephen