Why should the military budget be increased?
A lot of outdated equipment, a lot of old faulty equipment, big training and maintenance deficiencies, and other kinds shortfalls all over the place. Multiple ship collision incidents that have happened in the past few years that are in no small part due to bad maintenance, training, and equipment due to constrained budgets that force the military to compromise and triage where it spends its money. It should not be doing this just to achieve basic preparedness.
The idea that the US has more military capacity and money than it could need or desires is just fantasy. Moreover, it's downright detrimental to the actual functioning of the US army, not just because it results in inefficiencies due to lack of funds, but also because it results in reluctance to bring inefficiencies into the light and deal with them because of fears of reactionary budget cuts.