Things are getting contentious around “the horseshoe,” the nickname for the area where aldermen sit in the Springfield City Council chambers. Alderwoman Lakeisha Purchase issued a call Tuesday night for her colleagues to show more respect to one another. That came after Purchase had a tense exchange a week ago with Alderman Shawn Gregory over who’s causing problems for residents and businesses in some city neighborhoods. Gregory apologized for interrupting Purchase, but said he stands by his comments objecting to her characterizations of homeless people in the area. Meanwhile, a debate over changes to zoning rules for some cannabis businesses became personal when Alderwoman Kristin DiCenso said the issue was being pushed by an alderman whose son has an interest in such a business.