Do combat arms soldiers look down on fellow combat arms brethren if they have deployed and not been awarded a combat badge/medal/ribbon?

Most do, to be truthful. Most guys with a CIB/CMB look down on (or at least look sideways at) people with a CAB, and everyone looks down on (or sideways at) people without any badge. I don't fully agree with it, and have known some real great Soldiers who don't have any validating heraldry on their uniform.
But fairness aside, especially in maneuver units, it makes some sense to at least have a bit of deference to folks who have done the maneuver thing for real. I don't buy into the looking down on others thing, but I also don't really buy the "we're all the same" thing either.

Everyone gets my Respect. Some things get my attention. Badges, Deeds, Reputation, they are all items of validation, and pretending otherwise is overlooking some realities of humanity I think.

We definitely size each other up by what is worn on our chest. My personal story is I was an 0311/0369 Marine for 8 years 3 combat deployments in both Iraq and Afg. Got out, went National Guard as 92G (cook) can't wear a CAB or CIB or combat patch. So in my BDU's it looks like I have never deployed or have been awarded a combat action ribbon. I defiantly notice a difference in soldiers after they find out my history. Back to answer your question do they look down them? I think some do, but not all. I have learned over time if someone is trying to degrade you because you are lacking a piece of flare it is because they are childish and do not understand how the military works. Does the person that gets the CAB, CIB or CAR for a mortar round landing 800m away have any more combat experience than someone that has been at live fire range?

That is how it works. Does it mean it is right? No, but then we gravitate to those that are successful. We view those with badges and tabs as being successful. Comparing those with all of the badges and tabs to those without would mean that those without them are not as successful or experienced. As an Infantry Officer is it expected that you are Ranger qualified. If you don't have a tab then you are viewed lesser than your peers. Now, as a National Guard Officer I was one of few in my home state with a tab. At the time when I was drilling I was the only PL in my BDE with a tab that I knew of. In that case I was viewed in a different light.

I currently work with a group of soldiers that all but a couple have combat time and all of us are Ranger Qualified. I can't say I have seen a group of soldiers on their level. So if you were to see one squad that all of their soldiers were Ranger Qualified and one squad that no one was Ranger qualified I bet money that most people would opt to work with the squad with the Rangers in it.

I don't think we look down on those that don't have the awards but we look up to those that do have them. If a person feels they are on par with them that is their response. Tabs and badges may not correlate to being a better soldier, but it is a good maker.

Being honest, the pic I posted is my uniform. I am about to go back into the operational Army and out of the TRADOC world. If you could pick your PL and you saw a PL with my qualifications and skill levels surround by 5 brand new LTs without them, once again, you would naturally gravitate to the person with them.

I don't envy anyone with more badges or view them differently. If you are a jumpmaster and pathfinder then they can run a DZ. In that case they are more qualified than I and can accomplish task I can not. So why would be upset if they were view more of an asset than I. They are. I chose to go into the Airborne Infantry world. Schools are easier to come by. Some MOSs don't have that option. But then they should only look as far as their peers and not the rest of the Army. There is always someone better than you but then there might be a lot of others that don't have your drive an passion that are not as productive.

I hope this explains it well enough.