Aggregator sites like coinmarketcap and livecoinwatch often show trends of greatest gainers/losers of the day/week/month/year. However, coins with almost dead marketcaps are prone to manipulation.
Why don't these sites remove such coins?
Just scroll past > 1000 and see some coins with one or two extremely low-cap exchanges, which were quite popular at their time. Their ANNs haven't had activity for years, but once in a while their graphs have spikes showing some pump and dumps by unknown forces. Definitely some people got burned there.
The least they could do is have a page for these types of coins, and remove them from the normal trending and other stats pages.