The 99 page report upon which the 4 page memo was based has been released and has been analyzed and does not indicate the concerns are regarding raw intelligence.
President Trump wants us to be able to read the 4 page memo. I stand with President Trump.
The four page "Nunes memo" (not necessarily by him, just convenient shorthand) and the 99 page FISA Court opinion probably share some evidence, but the 4 page memo is not "based on the FISC opinion."
Seriously, most of what is on the internet is junk. It is tough slogging to figure out what is really going on. I think the ratio of mis/disinformation to "good stuff" is probably on the order of 1,000:1 or 10,000:1
Look for base sources. Even the junk purveyors occassionally cite and link to the raw underlying data.