++ I pretty much agree with everything you've written here except for posting in a different section. Your suggestion of a preface along the lines of "I saw X, it inspired me to write Y" might go some way to mitigating the downvotes of his posts; however, I tend to agree with other responses: bad code and forcing unwanted presentation preferences on others will still garner downvotes.

Maybe if the preface specifically stated it was code intended to be compatible with 5.004, TinyPerl, or other; and included an exposition of choices such as:

• I used $^W to generate warnings. The lexically-scoped warnings pragma is preferred but is unavailable: <corelist warnings output>
• The 3-argument form of open is unavailable: https://metacpan.org/release/CHIPS/perl5.004/view/pod/perlfunc.pod#open-FILEHANDLE,EXPR ...
• And so on ...

His posts would probably attract (more) upvotes; although, all of the <font>, bgcolor=, and other annoying and unwanted presentation artifacts would also need to be absent. Other considerations, such as appropriate use of <readmore> or <spoiler> tags, and disuse of inordinately verbose (wall-of-text) sections, would be well-advised.