There's no doubt that it's really the case and I think CMC get a hard time to filter those exchange who feed there the data but maybe people should be considerate to that since they are free to use anyways. But since the cap still continuously growing for sure many people get aware about the cryptocurrency and this is a good sign for more adoption.
There is a huge number of investors in the entire globe and that number is consistently rising which is getting more investors on board. In this situation, many people have a tendency to invest in these high volatile markets to gain higher profits than any other investment source and hence we could see a ascending order demand for the cryptocurrencies which always keeps on rising the market cap.
Moreover, a number of people are able to multiple their capital by actively investing into the markets and such people always prefer to reinvest more than 75% of their earning into the markets again which keeps on rising the marketcap as the time passes by.