So that Chaur Sahib becomes a symbol, symbol of king of kings. Do you see any reason for the jyot to be a symbol as well? Also does one person's or a group of peoples wrong interpretation of jyot make it wrong? Look up Gurbani on Chaur Sahib. Sohila Sahib speaks of Chaur Sahib and says the wind is my (Akal purakh) Chaur Sahib. Listen to what Bhagat Kabir ji has to say on Chaur Sahib. Also ask yourself, who was this reference of Chaur Sahib and jyot referred too. What were these people doing wrong, who were they doing Chaur sahib over and who were they lighting the jyot for.
Beginners and missionaries make the mistake of comparing Sri Guru Granth Sahib ji to the hindu worship of a stone/devi/devta. They ignorantly see both as the same and say....look Guru Sahib says its wrong (what is wrong for one is wrong for the other), but never pay attention to the context surrounding the action of why it's wrong. They have no depth to their understanding of Gurbani. Many newcomers fall for their foolishness because they don't know better. It's always best to go straight to the source, Gurbani.