Assalamualaikum,There are some negative stereotypes about a certain group of people whom are good sunni muslims. For some of those people , the stereotype is somethat true, but alot of them the stereotype on them is not true. What if a person feels that he will be negatively be affected by those people if he dresses like them( i.e. by fearing that he would grasp some of those negative stereotypes as well); eventhough he knows that there is no harm or benefit except by the will of Allah alone (swt)? Will this be considered secret fear which makes a person a kafir; since some people the bad stereotypes doesn't apply to them and so I won't be affected by them and I still get that feeling of fear when I dress like them?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

What you mentioned is not among the fear that involves disbelief.

The criteria of fear that involves Shirk (polytheism) that takes a person out of the fold of Islam, as Ibn Sa’di said in al-Qawl as-Sadeed:

“It is the fear that is the same as fearing Allah and being a slave to Him, and it is drawing closer with that fear to the one whom he fears; for example, like the one who fears that the dead person in the grave may inflict him with some harm, or that this dead person will get angry with him and take away a blessing from him.

We advise you to repel these whispers, ignore them, and seek to treat them.

Allah Knows best.