I want to second this great perspective. I’ve been in university ecology and biology departments since 2009, and from the level of undergraduate student to professor, we often want to illustrate lectures, websites, public and academic presentations with photos. I have often used wikimedia photos and other photos licensed with creative commons in my presentations.
We’re in the midst of a biodiversity crisis at a global scale. Photos can help educate and inspire others about the wonderful species that we share the planet with and that we are losing all too fast. I understand that it’s hard to make a living as a professional photographer–and if you are one you really should get paid and protect your photos. But if you’re an amateur like most of us here there’s little downside to sharing your photos as openly as possible!