If you don't understand that barring a conclusion from receiving federal funding is effectively barring the research itself, then you don't understand academic research. Even if you legitimately don't find gun control to be a solution from your research, that you would lose your funding if you did means there is necessarily a financial incentive with no basis in fact to have or not have certain results - invalidating the research. The actual effect is that it bars research into gun violence, even if that is not the letter of the law.