おいらが書くならこう

@echo off
setlocal enabledelayedexpansion
for /f %%a in (delete.txt) do set list=!list!,%%a
set list=%list:,= %
for /f "delims=" %%b in (bass.csv) do (
set "line=%%b"
set /a flg=0
for %%b in (%list%) do (
echo !line!|findstr /b /v "%%b">nul 2>&1
set /a flg +=!errorlevel!
)
rem echo !cnt!
if !flg! equ 0 echo !line!>>output.txt
)
pause