Explanation is pretty short.
People are selling their alts because they want to buy more btc during pumps
Not all altcoins goes down when Bitcoin goes up. A lot of depends on altcoin by itself. Altcoin must be useful for people. It is necessary to create demand in altcoin that investors wanted to buy it.
There are ecological projects. Here is written how it is important to protect a nature and what have already been done for nature protection
https://moss.earth/blog/.
I think that demand in ecological projects will be big because it is very important to protect a nature.
I checked the price of MCO2 token. It is growing. Some people understands how it is important to protect nature and buy a big volumes of MCO2 tokens. You can check MCO2 token here