I also cannot believe other countries (other than China) dismount their troops from armoured vehicles and have them run either alongside or away from the vehicle and into danger zone.
And I also cannot believe other countries soldiers still sit on top of Armoured vehicles, don't they know they are supposed to be sitting inside ;P
So as you can see, it is not always the case by looking at and criticizing based on a few photos or video, it might be needed for various reasons - such as, not enough vehicles, they are entering less hostile environment, they are out of the vehicles to engage on enemies that are difficult to be hit by armoured vehicles (IFV), etc. All these played a part, right?
In fact, it was due to combat experiences that infantry, especially from the formal soviet block, tends to prefer sit on top of, instead of inside, an APC or IFV during transit, and dismount as soon as approaching or encountering hostilities.
Typical APCs and IFVs are poorly protected from anything other than small arms. One hit from an RPG from the side or behind could take out an entire squad sitting inside an APC or IFV. Visibilities from inside of the vehicles are poor, and mounted soldiers have very limited contribution other than firing from firing holes with restricted field of view.
The Russians in Chechnya found out that siting inside an APC/IFV actually decreases the soldier's survivability. With solders sitting on top during transit, they have a great view of potential dangers, and they can dismount very quickly as soon as hostilities struck.
IFV's true value to infantry is that it provides heavy support firepower, and a place to store equipment, a moving object to take cover behind---but not inside, during combat; and good mobility during transportation between combat. Its armour is really only useful for protection against opportunistic snipers and artillery shrapnel during transport phase.
Of course there are heavy IFVs and APCs with armour approaching or equivalent to MBTs. But these are heavy, have a large logistic footprint, and during combat, the infantry will be fighting dismounted anyway, so in general, other than low intensity anti-insurgent patrol operations where acceptable casualties levels are practically zero and soldiers generally sit inside most of the time, they are inefficient use of resources.