Disagree. If you can't handle criticism and only want praise, you'll never grow. If you release a product to the open public and it's not very good, but everyone is like, "Oh well, an effort was made." and people keep buying it with no negative feedback, what's to stop the creator from producing more low quality products? If you're discouraged by being told your mod sucks, maybe revaluate why that is. Does it not work in its' current state, is it of poor quality or causing issues with the game or other mods? Is it utterly pointless and just not worth one's time? Valid criticisms. Modding and sharing isn't about seeking praise, but you creating something for a game that you enjoy to improve upon and, if you so choose to, share it with others. I can understand down voting just for the sake of being malicious or hateful can be discouraging. But really, criticism like that should be taken in stride, especially if more people are positive about it then negative.
I'm not a modder, but I've seen the worst problem modders have isn't criticism, but having people harass them to finish and release a mod or update/patch their mods after a game update. People are rude as hell to modders in that regard, and many stop because of it. I'm not saying you shouldn't be upset or angry if your mods are being unfairly ratio'd with downvotes, but don't be discouraged by some negative criticism now and then, especially if it is constructive.