Why is TAMIL SIGN VIRAMA (pulli) not Alphabetic?

[Richard Wordingham via Unicode]

On Mon, 28 May 2018 16:13:43 -0600
Doug Ewell via Unicode <unicode at unicode.org> wrote:

> Richard Wordingham wrote:
> 
> > The effects of virama that spring to mind are:
> >
> > (a) Causing one or both letters on either side to change or combine
> > to indicate combination;
> >
> > (b) Appearing as a mark only if it does not affect one of the
> > letters on either side;
> >
> > (c) Causing a left matra to appear on the left of the sequence of
> > consonants joined by a sequence of non-visible viramas.  
> 
> Most of these don't apply to Tamil, of course.

They all apply to க்ஷே  <U+0B95, U+0BCD, U+0BB7, U+0BC7> TAMIL
SYLLABLE KSSEE.  There are four other named syllables where they all
apply.

Richard