Can understand that, but it has been reported that they ended up adding 1,094 Kg of boric acid. More then they originally estimated would be required. That does not seem to be a well calculated preventative maintenance procedure done partially for show.
1094 sounds like a lot of mass, but you have to remember basic chemistry and physics. First, remember that the chemical formula for boric acid is H3BO3. That means that only 18% of the weight of the molecule is boron. Next, remember that only 20% of the boron is of the strongly neutron-absorbing form, 10B. That means of the total 1094 kg of boric acid, about 3.5% of that mass, or about 38 kg, was of a form that strongly absorbs neutrons. When you consider the volume of the pressure vessel, or even the volume of the mass they are trying to affect, 38 kg of material spread over that isn't a terribly large amount. If it was more than originally expected, my guess is they wanted to be conservative on the chance that some of the water carrying the material might evaporate or be diverted through the complex geometry without reaching all of the places they wanted it to get to if they used less.
Now, as Obamalamadingdong would say, here we have a teachable moment. We are better if we first consider the science and run the numbers before we jump to emotional conclusions (1094 kilograms is a lot of mass, more than they expected, therefore they must be lying, putting on a show). While doing so may be emotionally satisfying because it validates a personal prejudice, it can lead you away from the truth.