Like Badger stated, oxygen is not an explosive gas.
Yes, it can greatly accelerate the cumbustion process of materials. In fact, pure oxygen can cause things that would not normally burn, to actually combust. But there needs to be a set of conditions existing for this to happen. You need a fuel souce like a hydrocarbon (shock oil) and an ignition source before the combustion can take place.
Compression alone can cause combustion of a hydrocarbon when mixed with an oxidizer such as pure oxygen. But, the levels of oxygen in atmosphere aren't enough to allow the spontaineous combustion to occur. Primarily becasue other items such as nitrogen (78% of atmosphere by volume) exist and these items absorb the heat of the reaction such that it hinders the combustion process.
Using wet air (straight out of the compressor) will hinder this process even further since water is one of the best heat absorbers there is. However, since there are other molecules available to absorb heat (nitrogen, argon, etc) in the atmospheric charge, we need to consider completely ridding the water as it can cause other major problems in a shock bladder.
Look at your forks...they have a fuel source (shock oil) an oxidizer (air chamber on top of the shock) and compression going thorugh stroke, yet they don't explode. Becasue of the conditions I explained above. However, when we mix the oxygen with the hydrocarbon gasses are released as a result. These gasses are what hiss out of the bleed holes on top of the shock when we open them. Even after you bleed these residual gasses off, there has been oxidation and the oxides left on the hydrocarbon chains can be very abrasive to valves, shims, housings, etc... This is why we need to change out our fork oils often.
On tire pressures...when we fill a tire with atmospere, the moisture that remains can cause tire pressure to change as much as 10-12 psi with temperature change. That is why nitrogen or dry air needs to be used in tire fills when we need the pressure to remain stable throughout temp changes.