A St. Louis man brutally killed his own kitten Friday morning at the Belleville MetroLink station after he was told the animal could not ride on the train with him, according to St. Clair County police.The Belleville News-Democratreports that DeCarlos Edwards Johnson-Foston, 23, allegedly approached the MetroLink platform with the kitten on his shoulder when a security guard stopped him and explained that the animal would not be allowed on the train. In response, Johnson-Foston violently threw the animal to the ground, then stomped on its head.…