I think he means Pexels search sucks, not yours. Although he/she is not clear.

Your site does not look like it was made by a beginner. Seriously, is this what beginners can do?

I just did a side by side comparison searching for "ashtray", and your Librestock search actually finds ashtray photos from Pexels that not even Pexels search returns. So I'm quite confident that Pexels search sucks and yours does not suck.