This is a blog proposal to know of Princess Celestia (and even her human counterpart Principal Celestia) as Pure Good or not/
Who is she? (they?)[]
(Princess) the co-ruler of Equestria along with her younger sister Princess Luna, both of whom are responsible for raising the sun and the moon. She is the mentor of Twilight Sparkle, whom she addresses as her faithful student.
(Principal) the principal of Canterlot High School.
What'd she (they) do?[]
(Princess) Over a millennium ago, Celestia and Luna discovered the Tree of Harmony and took the Elements from it to defeat Discord. Afterwards, Celestia had to use the Elements herself to fight Luna, who had become Nightmare Moon.
At the beginning of the series, Celestia was no longer linked to the Elements of Harmony so she sent Twilight to Ponyville so that she find five ponies who could help stop Nightmare Moon. Once the Mane Six restored Luna to her true self, the two sisters were united once again.
She and Luna even banished King Sombra from ruling the Crystal Empire.
(Principal) Celestia appears as the principal of Canterlot High School. When Twilight's stolen crown ends up in Fluttershy's hands, she turns it over to Principal Celestia for safekeeping. Twilight goes to Principal Celestia about this matter, and Celestia explains that the only way for Twilight to get the crown to be voted Princess of the Fall Formal.
At the Fall Formal proper, Principal Celestia congratulates the school students for fixing up in the gymnasium after Snips and Snails trashed it earlier, and she announces Twilight Sparkle as the winner. She later commends Twilight for her role in defeating Sunset Shimmer.
In Equestria Girls: Rainbow Rocks, Principal Celestia first appears walking into the gymnasium with Vice Principal Luna to check on the students making signs and posters for the CHS Musical Showcase. She expresses hope that the showcase will be even better than the Fall Formal, inadvertently reminding the students of Sunset Shimmer's actions.
After the Dazzlings' arrival at the school, the Rainbooms try to warn Celestia and Luna about their true nature, but by the time they are reached, they have already been hypnotized by the sirens' song. Celestia and Luna later serve as the judges for the Battle of the Bands, and the Dazzlings hypnotize them and coerce their decision in favor of the Rainbooms instead of Trixie and the Illusions.
In Equestria Girls: Friendship Games, Principal Celestia and Vice Principal Luna attempt to raise school spirit with a pep rally before the Friendship Games take place, but they are unsuccessful until Rainbow Dash sings an uplifting song and ponies up.
Later, she gives Principal Cinch, the headmistress of Crystal Prep Academy, a tour of CHS, during which she sees a girl that looks like Twilight Sparkle. Cinch refers to this Twilight as her student, and Celestia believes her to be Twilight's twin sister until Pinkie Pie confusingly explains that she is the Twilight from the human world.
Celestia judges the Friendship Games with Luna, Cinch and Dean Cadance. She denies any involvement of magic in the games, putting her in direct opposition with Cinch. When an incident results in Twilight transforming into Midnight Sparkle, Cinch demands Celestia's forfeit, but Celestia holds her own against the duplicitous CPA principal. In the end, she declares both schools winners and welcomes the Twilight of Crystal Prep as Canterlot High's newest Wondercolt.
In My Little Pony Equestria Girls: Legend of Everfree, Principal Celestia serves as a chaperone alongside her sister Luna during Canterlot High School's field trip to Camp Everfree. She and Luna are stated to have gone to Camp Everfree themselves when they were younger, and they have fond memories of the camp and contributing a stone sundial as their traditional camp gift.
Final Verdict[]
I'd say yes. She (they) shown true kindness, care and support to everybody.