If intentional defacement was priority number 1, why didn’t they simply target the top sections of the wall and allow the fluid to drip down, or were there many people around so they had to keep cover? I do not know, only from what I see from these pictures as if the fluid was towards the bottom.
That is what I think.
The person who did it probably stood for a while watching, looking for an opening where there might not be many people around, especially late at night.
Then they had to get close as if they were reading...holding the squeeze bottle in one hand and randomly squirting.
This makes a lot more sense than a damned weed whacker.