IMO "My income is more important than the environment" is not the correct summary. The actual situation is this:

1) A youtuber needs a certain amount of income to be able to afford the time to create their content. 2) Selling merch works way better than asking for donations 3) The positive impact of having the informational videos far outweighs the negative impact of creating and shipping the merch.

You can of course criticize the viewers for (2) and if you think spreading information has a low impact, you can question (3).