There are multiple reasons to avoid the shot. Some are religious, some are not.
All of the vaccines were developed using aborted fetal cell lines, so that becomes a moral and religious issue for anyone who is pro-life.
Non-religious reasons involve various issues. First, the vaccine presents a greater risk for myocarditis and blood clot issues than COVID itself for people under 30 who are of good health. Second, none of the vaccines available in the US are manufactured with cGMP standards, so dosage quality can vary dramatically. Third, the one vaccine that received FDA approval isn't even available (Comirnaty). Pfizer only produces the EUA version, which has no legal liability for them for things like adverse events. The Comirnaty version does have legal liability due to FDA approval.
There are issues beyond that, but it's not about "wimpiness." It's about a product that is faulty and which you have no recourse if it harms you. To be honest, it's about risk assessment and intelligence.