Why are you getting your jimmies rustled for no reason? Stop getting offended over nothing. They didn't say "PHP developers are makers at heart. No one else is."
The sentence just sounds as if you paid $5 someone to write you an intro to a technical matter because you didn't know what to to use.
The sentence is general and without point. Because it is coming from a technical company and is aimed towards technical people, yes, I find it ridiculous.
If the Ruby on Rails blog made a post saying "Rubyists are makers at heart." would you complain?
Last:
Heroku != blog of a random startup
Lead sentence != middle of post
I won't continue as this leads nowhere.