Is it allowed to post Islamic content, such as poetry and art, on social media without mentioning the original poet and artist or deliberately removing their names?
If the person who is posting such material claims falsely that the material is his material, it will a lie and a sinful act.
If he does not claim any wrong claim but he is just posting a material for the benefit of people, with out harming any one, then it is allowed to spread useful knowledge which helps people and does not cause harm to any one.
Wassalam.