The Tzitz Eliezer wants to say that but it is very puzzling. Does it show a lack of bitachon for someone to undergo any medical procedure?The question is whether cosmetic surgery is considered a medical procedure that would would allow wounding the person. This is a machloket among the poskim. See “Judaism and Cosmetic Surgery”by Daniel Eisenberg, M.D. online.
Who are these people who “frown upon” it and what is their basis? If it is muttar it is muttar. If it is assur it is assur. A person might be able to be machmir on himself but he has no right to force others to do so. If it is muttar, let them frown. The muscle exercises might be good for them.