Why would the man who doesn't want the wall ask the neighbor to rebuild it? Might he want something more than just a hand with repair work?

The speaker asks his neighbor to help him mend the wall.
It's something they do together every year. It seems that the speaker doesn't see any
point in mending the wall, but his neighbor remains behind his old
saying:

He
only says, 'Good fences make good neighbors'. 
Spring is the mischief in me,
and I wonder 
If I could put a notion in his head: 
'Why do they
make good neighbors? Isn't it 
Where there are cows? 
But here there
are no cows. 
Before I built a wall I'd ask to know 
What I was
walling in or walling out, 
And to whom I was like to give
offence. 
Something there is that doesn't love a wall, 
That wants
it down.'

Yes, it looks like
the speaker would want something more, or, at least, he would like to stop mending a
wall which, from his point of view, serves no purpose.

The
poem is a comment on isolation and being stuck with ideas that may have had some purpose
in the past but no longer hold in the present. The speaker sees his neighbor as a
"savage" who moves in "darkness," as someone who is ruled by outmoded thoughts and lack
of originality. It should be noted, though, that most of my students, when we read the
poem in class, side with the neighbor. They agree that "good fences make good
neighbors."