None of those comments are complaining about PHP being slow at repeatedly writing a string whose length is a multiple of the page size to standard output. That

None of those comments are complaining about PHP being slow at repeatedly writing a string whose length is a multiple of the page size to standard output. That is a pretty niche case, and hardly refutes even the complaint that PHP is slow, much less all the complaints about PHP that aren't related to its speed. FWIW, when I run the tests there's no substantial difference between Perl, LUA, or PHP.