[quote=@Roach]
My own top contender for the worst writing advice is actually more about critique on the web: Any advice in [b]which a critic takes a piece of writing and rewrites it in their own style just to feed their own ego.[/b]
[/quote]

This sounds like you're playing the role of a mind reader.

[quote=@Roach]
[b]There's no reason why anyone should say or imply that 'this would be better if you did it my way' when doling out specific advice on the internet.[/b] 
[/quote]

You know, except when people either personally ask for that advice specifically. Enter a creative writing contest, or anything that invokes competition and begs to be critiqued for such a thing specifically. Or, perhaps how literally every single writing/literary agent works, when it comes to endless revisions required to getting one's writing published. Then, it benefits the writer significantly. But sure, all other times, no reason to rewrite things whatsoever. ^-^'

(Or when you're writing a fan fiction, because hey guess what, that's rewriting/changing someone's established 'voice/cannon' and making it your own. And that's okay too.)

[quote=@Roach]
[i]Never[/i] stifle an author's voice. It's just unbearably rude.
[/quote]

This sentiment could easily boil down to "the author can never be wrong/all writing quality is subjective."

But all suggestions can either be taken with sheer hostility and ignored. Or they can be evaluated and worked upon. (And I can tell you the latter makes you more successful in every avenue and medium.)

Because, just perhaps, not everyone that critiques or offers personal advice is thinking "how can I feed my ego today". But does it, in order to help someone get better. (Or at the very least, get them to understand a different perspective.)

And, tell me this...

How can you critique anyone's writing choices whatsoever, when you aren't allow to seek or offer changes? 

Because [i][b]all[/b][/i] critique and advice does this. With literally every example you can think of. You are looking, or expecting someone to update something.

So for example, why is "your sentences are complicated and vague" more helpful and acceptable to say, than "Your sentences complicated and vague, so if you don't mind, let me provide you potential solutions as to precisely what I'm talking about." 

In both cases, the person giving said advice, is asking the author to change their original work. Likely to make the author's sentences more clear and concise. So assuming both people are doing that in good faith. Where one often gives no examples and provides no solutions. And the other does so. Is the first better because...they put less work into their giving their advice? Is it nicer to leave an author clueless on what the former even wanted? Simply because it there's the chance it will hurt one's feelings a little less, from the sheer lack of context for them to dwell on?

I'm all ears.