in naziism millions of jews were killed because just one man who probably had jewish blood in his veins, wanted them killed. in communism it is individuals who are killed, who may not agree with the ideology.

If we want to get more topical, just look at NETFLIX. There are dozens and dozens of movies on there that claim to be about WWII. On closer inspection and when you watch them you soon realize that the movies are just an excuse to constantly keep the holocaust in view and in the mind for as many that will watch the movies and documentaries.

Communism is alive and well and active. The Nazi party hasn’t had 80 more years to distribute propaganda.

This is a very broad issue and in a way is the wrong question. The National Socialist Party (nationalsozialist) ie Nazi Party was a Fascist Party which began in Germany in the 1920s. Fascism ( an extreme right wing political philosophy) started somewhat earlier in Italy. Right wing politics as a concept has however been around much longer as have left wing political philosophies. ‘Modern’ communism really began with Karl Marx (hence Marxism) in the 19th century. A better question is therefore why left wing politics is not feared as much as right wing politics.
A very short answer to your actual question is that Naziism is associated with Hitler and the Second World War and all that entailed ( death, destruction, concentration camps etc). Fascism is similarly discredited for broadly the same reason. It could be pointed out that concentration camps were not new, have been used in Russia since WW2 and and that under Stalin people were killed in the hundreds of thousands (almost certainly even millions). However proponents of left wing ideology prefer to side step that one.
So why is left wing politics apparently so appealing to some. Again to keep it short, one reason is that it sounds good especially to the gullible young with no life experience, to the poor and to academics who focus on idealistic principles rather than realty. Ideas such as shared ownership, everyone having a job and earning the same, everyone being looked after by the state and the whole nation being one happy family can be appealing. But it’s not real life and takes no account of how people are in practice. It might work in a village but it doesn’t translate into a country with millions of people.
Right wing politics can be harder to sell, opportunities for all, the best rising to the top and rewards for those that make it. Market forces dictating much of society, much less, if indeed any protection from the state. Appealing if your able, much less so if your not. Arguably however it takes into account the reality of how people are and it encourages innovation, wealth (in total) and incentivises people to perform.
In the above, I am not claiming that my description of left/right wing politics is how they actually are in practice) I am simply talking about why they do or don’t appeal conceptually. One other factor however is that what are labelled as for example communism or fascism, left or right is often misleading. Extreme left and extreme right can seem to form a circle merging to form something that in reality is something else. For example a communist state with what is virtually a single head, huge rewards for some and grossly unfair treatment for others and which could be almost indistinguishable from a fascist state. We don’t actually have to look far to see examples.

Muslims and Communists both have in common that their doctrines call for lying about the doctrine as necessary to persuade a supposedly ignorant public for their own good. And Communism has its stated goal a kumbaya kind of Utopianism that is attractive to gullible idealists. Until these kids have enough life experience to realize that history is correct, they are ripe to be brainwashed.