What makes the USA safer?

a) the DOD spending a bazilion labor hours planing, promoting, and participating in these cultural events; or

b) Spending that same bazililion hours in training and preparedness for foreign operations already underway or that may be deployed on a moments notice, adapting and becoming proficient in new weapons and other technologies as they are deployed, and so on. ie the mission critical stuff, not the virtue signaling stuff.

Convince me that a) is the better investment of the DOD's time and focus.

I don't have enough knowledge of what happens at the DOD for those events, i.e. how much time and resources are devoted to them and for what, to be able to give a informed opinion on those specific matters, but wouldn't those same arguments apply to other holidays, which are not being stopped? And you would also need to consider positive effects on morale of recognizing the various cultures and ethnicities that make up our country.

I do have an informed opinion on what does NOT make the US safer:

1) Let's start with electing an erratic, unstable, bumbling, aging, crooked megalomaniac reality TV star as President and handing him the nuclear codes and surrounding him with a bunch of loyalists who will do whatever he says

2) Appointing a TV news personality (possibly alcoholic) who calls those who disagree with him politically "America's domestic enemies" as Secretary of Defense

3) Destabilizing the world order in so many ways not in our favor ultimately--frightening our allies with impulsive actions and petty squabbles, pulling out of the World Health Organization, pulling out of the Paris Climate Accord, leaving our allies unable to trust us and looking for other places to turn to get the kind of help and stability that they used to get from us

4) Letting a bunch of violent right-wing criminals out of jail on pardons

5) Destabilizing the domestic order with a flurry of poorly thought out and executed and often illegal Executive orders, relaxing environmental standards that will worsen air quality, water quality, etc.

6) Ignore scientific consensus on climate change

7) Divisive rhetoric

And on and on...it's been well-covered here. We're halfway screwed already. Hopefully it won't get worse than that.