On the contrary, that should convince them that Lemmy has as much content as Reddit!
I don’t think the math checks out on that.
While quantity of content is essential for a community like this, many Reddit refugees, myself included, turned to Lemmy due to Reddit’s changes which empower repost bots that regurgitate content in high quantities but the quality of the content is diminished by it being reposted content that the audience has probably already (even more so diminished if it is uncredited).
Your Lemmy posts with an i.redd.it link or a preview.redd.it link don’t directly link to a page that identifies the OP. While there is a button on the page that should connect to the original post, this button instead takes users to the App Store (or equivalent) to install the Reddit app, even if the Reddit app is already on the device. I’m also just now seeing that the Memmy app for Lemmy does not show when a post is hosted via an i.redd.it link and it instead presents the post content as if it were hosted native to Lemmy, so that is an oversight on my behalf and I see now that I had mistaken some of your posts as being uncredited copies.
Other users are apparently under the impression that content is OC if it is presented this way without a direct identification of the source. This commenter thought you had made the content in the post, and you could have clarified in a reply and said that somebody else made it. Alternatively, being as clear as possible in the title of a post about who made what is the most direct way to avoid that confusion.