Conversation so far:
How was the Replacements Band formed?
The Replacements' began in Minneapolis in 1978, when nineteen-year-old Bob Stinson gave his eleven-year-old brother Tommy Stinson a bass guitar to keep him off the streets.
How did Bob and Tommy Stinson find the rest of themembers?
That year Bob met Mars, a high school dropout.
How did Bob and Tommy Stinson along with Mars find their fourth member?
The band eventually found a vocalist, but Westerberg wanted to be the singer and took him aside one day to say, The band doesn't like you.“
Did Westerberg just invite himself in to the band?
The vocalist soon left and Westerberg replaced him.
Was that all of the members of The Replacements with Westerberg as the vocalist then?
In contrast to the rest of the band, the relatively disciplined Westerberg appeared at rehearsals in neat clothes and insisted on practicing songs until he was happy with them.
How did the Replacements come up with the name for the new band?
After being banned from a venue for disorderly behavior, they changed the name to the Replacements.
Did The Replacement's release and singles during this time?
The Replacement's soon recorded a four-song demo tape in Mars's basement and handed it to Peter Jesperson in May 1980.
What else significant happened to the band during their developement besides releasing a four-song demo tape in Mars' basement?
Dogbreath changed its name to the Impediments and played a drunken performance without Tommy Stinson at a church hall gig in June 1980.

Question: Why did they exclude Tommy?
Self-contained rewrite: Why did they exclude Tommy Stinson from the performance at a church hall?