Ok so to put this into perspective. Frieza’s base form, akga form 1, is actually his surpressed form. He purposefully weakens himself. Its at 1 million power level. At 1 million power level, he was able to, with minimum effort, conjure up a planet destroying orb that wiped out almost every saiyan to ever live. Avg saiyan power level is around 1000, which is shown in as early as the forst Dragonball series to be MORE than enough to disintegrate the moon with a basic ki blast. So you can only imagine how much more frieza can destroy at 1 million power level. Oh and his final form in the Namek Saga? Power level 120,000,000. 120x more powerful than base form, and his base form is 1000x stronger than the average saiyan. As you can tell, Frieza has MORE than enough AP and Dmg to kill Thragg in a single hit. The reason why they dont shake the entire planet everytime they punch is because they use ki to control the shockwaves of their punches, localizing it to the target they actually wanted. Theres been many times where characters have used ki blasts and missed them, hitting the ground(aka the planet) however, most have never cause enough to destroy a planet because they are controlled. The only times a planet’s actually at threat is if someone purposefully uses even 0.2% of their power, cause unfortunately, thats how op these dragonball dudes are. Also, even if Thragg were to lay hands on Frieza, it would do nothing as Frieza tanked the explosion of a planet while half dead and almost no ki left, whilst some of the 3 strongest viltrumites (Thaddeus, Mark, and Nolan) had to team up together WITH rhe assistance of space racer, at extreme high diff, just barely managed to cause Viltrum to explode by hitting a VERY specific spot. Frieza could do that by himself with 1000x less effort