Except that is definitively and verifiably not true. You're missing the part where parsers have existed for those 3 years and every (EVERY!!!) top group has used them. I'd argue every group that's cleared (minus maybe a couple outliers) before nerfs have had at least one person parsing. This is a large crux of your argument that's flat false.
The thing is, people want an official in game parser mostly to bring PS3/PS4 players the ability to do what the PC players have had the capability to do for ages, and that is gauge their performance as a DPS. People on PC who want to parse already are, so in reality, only PS3/PS4 players now receiving a parser would see any real change from this.
Now for the rest of your argument, it seems to me mostly more fear of abuse. As said more than once, abusive players are abusive players. They will find a way to abuse you with or without a parser. Why is parser abuse worse than non parser abuse? So what if it's another tool to use? They already have plenty of tools! Not to mention a lot of those abusers are the ones actually doing poorly. So having a parser will in many situations remove a tool for them to abuse you with.
The thing is, abuse will always be abuse. You can and should report it. GMs have been very good from what I've seen at dealing with actual abuse. Note: actual. Someone telling you your DPS is low is not abuse. It's simply stating a fact that probably hindered or blocked the group from completing the content.
I agree with what someone else said before. There will probably be an influx of abuse at the start, but that'll subside as GMs cut those people abusing it out. Although, to be honest, even an influx of abuse I don't think will be much. This is anecdotal, sure, but I've seen abusive players only 5 times in the time I've been playing, which was only a month or two after PS3 release. Maybe I'm lucky, but I feel if someone is constantly seeing heavy abuse, it's a sign that there's something you could work on. This doesn't absolve the abusers. They are still to blame, as acting that way isn't acceptable, but you can't control them. You can control you though.