I mentioned about load case 10 as the warning included that load case number. So if this load is something that in reality, cannot act in opposite direction, you don’t need to worry about it from the buckling standpoint.
Regarding your other question, the load can only reach the support at the bottom if the intermediate supports do NOT offer vertical resistance. The applied load at the top of the member will be transmitted to the bottom through the member which is a continuous column. The intermediate supports are just lateral restraints. On the other hand if you restrain the FY at these supports, then the entire vertical load will be picked up by the top most of these supports which is not the intent.
Regarding your other question, the load can only reach the support at the bottom if the intermediate supports do NOT offer vertical resistance. The applied load at the top of the member will be transmitted to the bottom through the member which is a continuous column. The intermediate supports are just lateral restraints. On the other hand if you restrain the FY at these supports, then the entire vertical load will be picked up by the top most of these supports which is not the intent.