Most of BlackRock's assets under management are invested in index ETFs. Index ETFs are essentially undifferentiated products. The indices are defined by other companies (S&P, MSCI, FTSE, NASDAQ, etc.) and you can get your index ETF from other providers (State Street, Vanguard, etc.) So in practice it's a fairly competitive market. As a result, management fees and margins are very low.

Investor activism is a way to promote more growth into active investments that are more profitable. If you are concerned about the climate crisis, you can consider those investments, but keep that in mind. Maybe I'm too cynical but I think it's really hard to be a ethical investor. You don't want corporations that exploit minerals or workers in the third world? That cuts you from Apple, Samsung, etc. You don't want to fund wars in the middle east? No government bonds. And so on. In fact if you were really concerned you would probably avoid those types of investments in the first place and focus on local businesses, etc. (but much higher risk).