Pushing a theory for political gain corrupts the scientific process. The supported side will get lots of funding while the other side struggles. This encourages researchers to backup the supported theory or risk loosing funding. It also gives the supported theory the appearance of being overwhelmingly supported by the evidence, even if it is not. In addition support or opposition for the theory becomes based more on politics than science. The result is that it becomes hard to find the truth, because no one is unbiased
The worst example is the theory of Man caused Global Warming. Favored by progressive politicians who see it as an excuse for increased government control and opposed by conservative politicians tend because of the associated big government political agenda associated with it.
The fact is that there is scientific evidence against man caused global warming and the entire global warming theory as well. The evidence also indicates that the solutions being pushed by global warming proponents are the worst way to dale with it even if their science is right.
The point is that the politicization of global warming has greatly hampered the scientific process by hiding and distorting facts making it hard to find the truth. This is bad for and destructive to science. As a result when ever science is politicized the process of science is damaged.