All of the top comments on Good Morning America will likely be deleted due to all of the people claiming the FBI had this shooter and the shooter's friend on a watch list. Apparently the shooter bought a firearm a week before doing this shooting.
Others have said his motive might be he is upset about Biden bombing Syria and that is why he did what he did. It remains to be seen what actually is happening, as always we will have to wait for more details to come out. All of these things that are being said right now are allegations and we must parse through them in the short term. Some details will be factual while others are not.
Twitter exploded into a rage of "it's a white mail trump supporter shooting people again". Many blue checkmark twitter personalities immediately jumped into the fray, seeing grainy footage of the suspect from behind being arrested. I didn't want to post a ton of screenshots of the bluecheck marks saying this, but here is a prominent one because she is Kamala Harris's niece saying it was white men who do all of the mass shooting.
Sources:
https://nypost.com/2021/03/23/colorado-grocery-store-shooting-victims-identified/