Programmers care about it because it adds extra noise to your program.
If you semantically, and naturally, communicate "end of statement" with a line break to human readers, why should you have to say it again with a semicolon to the compiler? Programming languages should focus on being DRY.
Lines of code are clauses not sentences. This is also true of poetry.
A sentence is more akin to a stanza in poetry, and a function in code.
While I could entertain an argument for lines ending in commas and for functions to end with periods there is no reasonable argument for lines to end with periods (is there a language where a line is equal to a function?).
APL, and to some degree Perl, are examples of languages where to you might consider a period half-way through a line.
I wasn't suggesting exclusive use of linebreak… Semicolon with no linebreak is fine, but semicolon + linebreak is 100% additional cruft. One or the other. Say it once.
If you semantically, and naturally, communicate "end of statement" with a line break to human readers, why should you have to say it again with a semicolon to the compiler? Programming languages should focus on being DRY.