How to partially merge similar items?

Questions
1

For polynomials：

-x1 - x2 - 1/(x1 \[Lambda] + x2 \[Mu]) + 
 2 (x1 \[Lambda] + x2 \[Mu]) + (Log[x1] - Log[x2])/(x1 - x2)

to get the result:

(x1 - x2) (-1 + 2 \[Lambda]) - 1/(x1 \[Lambda] + x2 \[Mu]) + (
 Log[x1] - Log[x2])/(x1 - x2)

Why can’t we handle it using this method?

-x1 - x2 - 1/(x1 \[Lambda] + x2 \[Mu]) + 
  2 (x1 \[Lambda] + x2 \[Mu]) + (Log[x1] - Log[x2])/(x1 - x2) // 
 Collect[#, {x1, x2}] &
2

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