> There is the universal hate for flash because it was used for ads and had shitty security

That's only one side of it. Flash was the precursor to the indie/mobile gamedev industry we have today (Newgrounds, Miniclip, Armor Games), before smartphones become ubiquitous. Not to mention some rather creative websites, albeit at the cost of accessibility .

Flash's only fault was it's creators were gobbled up by Adobe, who left it in the shitter and ignored the complaints people had about it's security issues.