Isn't Walt Disney Studios Motion Pictures the primary theatrical distributor in the US for Disney/Pixar/Marvel (newer)/Lucas films (newer)?

AND Shouldn't most of the releases show that as the first studio in the profile. (as long as reference is made in the credits or can be proven otherwise)?

For Example

Incredibles 2 currently shows Disney, Pixar Animation Studios

Shouldn't it be Walt Disney Studios Motion Pictures, Disney, Pixar Animation studios.

In the end credits it does show distributed by Walt Disney Studios Motion Pictures

Why would you list a distributor as a release studio?

Nowhere does the rules say list the film distrubutor first. Or at all.

Yes, the theatrical release studio (assuming there is one) should be the first entry for the studio entries.  Just like the publisher (content) should be listed first for media companies.

However, that doesn't mean this always happens with contributions.

I thought the contribution rules covering "Film Details" was explicit:
http://www.invelos.com/dvdpro/contributions/Rules.aspx?display=filmdetails

Under the section "Studios", it states as follows:
List the Studios in the following priority.
- Theatrical Release Studio(s)
- Production Company(s)

The process of making a movie available for viewing by an audience in theatres was the responsibility of the theatrical release studio company or its designated equivalent.

Before 1953, Disney films were distributed to theatres by external entities, such as Columbia Pictures (1930-32), United Artists (1932-37) and RKO Radio Pictures (1937-53).

From 1953, the Disney company took ownership of theatrical distribution by creating its own subsidiary company:

1953-1960  Buena Vista Film Distribution Company, Inc.
1960-1987  Buena Vista Distribution Company, Inc.
1987-2007  Buena Vista Pictures Distribution, Inc.
2007-        Walt Disney Studios Motion Pictures


So to answer CharlieM's original query, if the film's opening/end credits display "Distributed by ...." then add it in the profile as a Theatrical Release Studio company, followed by the film's credited production companies (as CharlieM suggested).

As others have already pointed out, this is not to be confused with the distribution of home media, which is covered in the Media Companies section of the contribution rules.

So Buena Vista Pictures Distribution is allowed since it is usually the last credit in the ending film roll.