Well, not entirely true since a lot of people actually showed actual reasons to NOT want ARAM bans back that could've justified why they were against it without being solely ARAM account users.
But even then, literally all of those reasons have blatent and utter flaws that make ARAM bans the best solution either way.
Amongst those mentionned reasons, there were:
1- The fact that an ARAM with every champions unlocked would be more balanced than anything we've got yet. Even if this one is particularly appealing and popular, this reason is utterly flawed because it got tested by Riot with very unsatisfying results (due to the presence of rerolls, rerolls pools, dodging, trading etc) and is a solution that Riot would probably never ever implement due to the loss of potential money from unlocked champions. In short, it is both inefficient game-satisfaction wise and very unlikely to happen. Bad reason.
2- The fact that Bans forced an additional 30 seconds to the gamemode... Do I really need to explain why this one is bad? Anyone who considers an additonal 30 seconds too long needs to calm the fuck down. Bad reason.
3- The fact that Bans supposedly made ARAM less... random? This one is a favorite of mine to see, since it doesn't make any sense at all. This one is based on the opinion that removing 10 champions from the roster makes it less random by reducing the total amount of champions. But since the banned champions are extremely often champions with a 10%+ pickrate in ARAM while several have a 5%- one and the roster is still at 93% integrity after an optimal 10 champions ban, we quickly come to the conclusion that bans, as far as champion pickrate spread is concerned, actually IMPROVES randomness. Also consider that ARAM never was and never will truly be COMPLETELY random. Bad reason.
4- The fact that you can't get X permabanned champion. This one too, doesn't make any sense, since some really fucked up weird people around here play ARAM, a gamemode based on getting a random pick... expecting to get a definite pick amongst 2, 3 or maximum 4 potential champions. This group potentially also regroups ARAM accounts, but I find it astonishing that some people complain they get an unanticipated pick in a gamemode where the goal is to get an unanticipated pick. In short, if you want a definite pick, don't play ARAM and never ever come again, the charm and fun of ARAM is to get a variety of champion, it's not about playing and throwing games until you want THE pick you want. Bad reason.
There are also some more, but those 4 are the principal ones. Just making this to go back on your statement:
the only people who were against it were the ones with ARAM accounts
As it turns out, the reality is far more horrendous, since there are also;
1- People with good intentions but who don't see the greater image,
2- Lazy people,
3- People who don't understand how ARAM or bans work
4- People who don't play ARAM for what it should be
... who also are against bans. So, my main goal isn't to remind people that ARAM accounts are bad and that they are literally everywhere, but to make people think on why they shouldn't be against bans since there's literally no reason to be against them other than unvalid and often biased reasons
, 
, 
, and 
and not have them permabanned every game when 
,
, 
are all at least as strong. Leave bans in and you might as well change the name to "All Mid" because there's nothing random about 10 bans followed by 10 rerolls so each team has a perfect team comp when half the fun champs aren't allowed to be played
for some reasons while nerfing champs like 
who is already meme tier before the ARAM changes, and they didn't address all problematic champs in that mode (
for example).
