It's not mean. His teammate Jay Howell started that movement and Wetteland embraced the phrase. There were several relievers like him, Rob Dibble, Dan Plesac, etc. is the late 80's and early 90's whose philosophy of pitching was "change speeds by throwing harder" and referred to themselves as the Brain Dead Heavers.
https://www.tulsaworld.com/archives/wetteland-living-life-to-an-extreme/article_111d8c68-7357-55b3-afd6-59542f409b57.html
"Howell enrolled Wetteland in the "Brain-Dead Heavers Club." Their motto -- "We are not relievers; we are brain-dead heavers." The idea, Howell said, is that changing speeds means throwing harder. "Once a heaver, always a heaver," Wetteland said."...