It is not that it is wrong. The idea is that when you copy someone else's text, you cite the author, and make a comment or brief analysis of what you are quoting, not just copy and paste and say the source or where you are getting that information from.
For example, you can place the copied text in quotation marks, once you finish that text, you proceed to make your personal contribution, interpreting, commenting, saying some experience related to what you are reviewing. If you don't enclose the text in quotation marks, readers will be lost as to which information is from another author and which is yours; I don't know if I'm making myself clear.
The idea is that you, as a content creator, give your personal contribution or interpretation of what you bring from another author, that enriches your post and for sure you will bring us great ideas by doing so.
It is always nice and interesting to read your opinions, experiences and ways of seeing the world.