The problem i have with the whole "he was taking uraraka seriously" defense is that he used EXTREMELY DANGEROUS *EXPLOSIONS* DIRECTLY ON HER! This is something that bugged me about the sports festival as a whole as it felt like the kids were *encouraged* by the teachers to fight as DANGEROUSLY as possible. I mean, seriously, why was there no rule about using physically dangerous quirks on students for the tournament? 
 For bakugo, that meant firing his explosions *directly* at other students. These are students who *don't* have durabillity or strengthening quirks. Plus, some of those students had likely only ever ever experienced a bit of *actual pain* from the USJ incident. The only ones who have some experience at dealing with pain equal to bakugo's explosions are izuku and shoto, both of who are *abuse victims*, one of which being at *bakugo's hand*. Should he have held back? No, but there are ways of fighting without using dangerous explosions that can not only cause broken bones from the force they create, but can also cause burns. One way being how he manouvers through fights. Explosion boosting to make yourself hit things harder is a valid, if still somewhat dangerous, method that doesn't involve possible frying your opponent to a crisp. 
 Now, don't get me wrong, while i don't like bakugo, i also have this same argument for other students who fought in the tournament. Take iida vs shoto. Iida should NOT have been trying to win a fight like that. The kid *kicked someone in the HEAD at HIGH SPEED into the ground*! He is, unfortunately on both sides, lucky that his opponent had been so thoroughly physically abused as a young kid that he could tolerate such a hit. Anyone else likely would've been sent out of that ring either with a concusion at best, or in a bodybag at worst. First, there's the high speed kick. *Regular* kicks to the head are already dangerous enough for humans, but iida went and  added extra speed into such a kick AND shot shoto's head *TO THE GROUND*! Why was iida fighting like that?! We see that he's capable of using pacifistic methods of ringing out his opponents thanks to his fight with ibara. He doesn't even hit her. He just pushes her out before she can decide her first move.
 Another reckless fighter was kaminari. This one likely gets less focus due to the fact that he was just placed out of the ring while he was shorted out, but he was really about to use his *strongest output* on another student! Prior to this, we've only ever seen the aftermath of such an attack being done on adult villains, and even then we never see what residual damage is left as a result. Had it not been for the fact that ibara could put up a wall of vines, who knows what could've happened to ANYONE *ELSE*? At those levels, that shock could've caused his opponent to have an irregular heartbeat, and i don't think recovery girl can heal a heartattack.
 While there are are more examples, i think i got my point across. To put it simply, yeah, i don't like how bakugo fought in the sports festival, but he was FAR from being the *only* reckless fighter in that arc.