Shorty,
Welcome to the forum. 
Hmmm … your code looks convoluted and confusing to me. How does your $KeywordList look like? And what output would you expect? How about using Select-String?
I’d start with something like this:
$SiteContent = (Invoke-WebRequest $SiteLoc -UseBasicParsing -Headers @{"Cache-Control" = "no-cache" }).Content
$SiteContent | Select-String -Pattern $Keywordlist