It’s not clear what claim is being made, but I would say that it’s up to whoever is making the claim to provide evidence that a certain protocol should have been followed.
Was this when Biden departed or arrived in India? If so, no US military other than flight crew would have been involved, as it would have been up to the host nation to provide honors.
Was this when Biden departed Andrews AFB? The Air Force Honor Guard manual does not dictate when rifle cordons are required.
Base honor guards are required to adhere to AFI 34-1201, which states:
11.3. Minimizing Frequency of Ceremonial Honors.
11.3.1. Formal welcoming ceremonies, when planned by appropriate authority for specific
purposes, are always appropriate when they are instrumental in improving morale or
maintaining national prestige.
11.3.2. In the interest of economy and manning, parades, honor cordons, motorcades, and
other ceremonial aspects, which involve large number of personnel and equipment, will be
held to an absolute minimum when officials entitled to such honors visit military
installations. (T-1). In general, full honors will be reserved for statutory appointees and
general or flag officers of the military services, for foreign dignitaries, and for occasions
when ceremonies promote international good will. It is the prerogative of the commander to
determine types of honors to be rendered. (T-1).
Departure ceremonies may be appropriate, but a president leaving from Andrews AFB has not typically been treated as such. In short, based on the above, forcing the Andrews base honor guard to suit up every time the president jumps on a plane is antithetical to maintaining morale. This is like waving goodbye to your spouse as they leave for a business trip, not saying goodbye to old friends who have been staying with you for a week.
I have no idea why the Marine honor guard would be involved in this at all.
In short, it’s going to be hard to provide proof because nothing says that an honor guard cordon is required every time POTUS boards air force one. Make someone show you something that says that.