I hate this argument, I do. When Pluto was considered "Not a planet." I had a different reaction that most people have: I was happy! Because deep down I always felt that Pluto shouldn't be considered a planet.

What are the facts?

Pluto is nothing more than a Dwarf Planet. Unfortunately, they did a vote on whether or not they should consider Pluto a planet. Which is something that should NEVER happen in science?
This almost led to the belief that we could "decide" whats best for science When Pluto doesn't match the required criteria for being a planet.

What is a planet

For an object to be considered a planet, IT must have three characteristics.

It must orbit around a Star
It must be mostly round.
It must have cleared it's neighborhood for orbit.
While Pluto successfully fits, 2/3 of these. It hasn't cleared its neighborhood for orbit.
At first, I thought these qualifications were a little silly, Even though I still feel that Pluto is a dwarf planet. But they make sense.

If Pluto IS A PLANET, How many planets do we have?

For people fighting to call Pluto a planet, You realize Pluto is in the Kuiper Belt, Along with a bunch of other bodies right?
Pluto is smaller than some of that stuff. Such as Eris. Then Makemake and Haumea are only slightly smaller than Pluto. Does this mean we should classify all the Dwarf planets as regular planets?
We'd have over 900 in our solar system alone!

Lets not waste our time

Calling Pluto, and the 900 other "Dwarf" Planets, Planets. Gives us this expectation, That we should study all of them in depth. As bad as I wish we had the resources, and ability to do that. It would be unreasonable.
New Horizons studied Pluto; Pluto wasn't left out!! Happy?
Imagine if instead of exploring further out there, we only focused on tiny bodies in our solar system?
We'd learn so little information that we could apply directly to humanity!
It's important for us to understand the deeper parts of the universe, To understand why we are here, And if there is life out there. These things would dramatically change humanity as we know it.

So no! PLUTO IS NOT A FREAKING PLANET!