Shirk means idolatry, to worship something or something other than Allah azzawajal. Anybody who commits shirk is a kaffir (a non Muslim).
Shirk is also the opposite of Tawheed and anybody who's Tawheed is not correct is not a Muslim.
Shirk is the highest level of kufr and the unforgivable sin.
A Muslim MUST worship only one god.
So Muslims cannot commit shirk and if what they do is actually shirk then they are classified as non Muslims. This is exactly why TTP, ISIS, AlQaida, Alqidainmaghrib, BokoHaram and the rest kill Muslims, kill muslim armed forces, blow up markets, shops, houses, mosques. They believe they are doing jihad and killing mushriks and not muslims.
Sajda or sujood means prostration. Allah almighty asked the Angel's and Iblis (satan) to do prostration to Hazrat Adam Alaisalaam. The Angel's did the prostration but Iblis refused.
This proves Sajda is not shirk or worship. Sajda of respect was allowed in Islam but only sajda of worship is kufr.
In Islam for 1400 years the rule have been changed, we cannot do sajda to anyone, even the sajda of respect. It is considered haram and not shirk as promoted. Only sajda of worship is considered shirk and kufr. So before accusations we need to ask if what they did was a sajda, then ask if they did sajda of respect or worship etc.
Kissing hands and feet in Islam is allowed. This is not forbidden. I encourage people to kiss their mother and father feet. This same way many people want to kiss their ustaad (teachers) feet.
So before calling people mushriks or accusing them of worship we need to investigate on what they are doing. Remember falsely accusing Muslims of shirk is a big crime. If we call Muslims as non Muslims then we can become non muslim If that person is actually a Muslim and not committing shirk.
May Allah almighty forgive our sins and guide us all. Ameen