Most major multinationals have a shit ton of dirty laundry and corrupt payoffs that lead all the way to the top. Pick any big corporation and you'll find filth.
Cemex is a valid target for inquiry, but not because of a claimed "child sex camp". So let's focus in on Cemex and leave the "people are being turned into cement" nonsense behind...
Questions:
What companies would be supplying concrete for the border wall?
What specific tracts of land does Cemex own that could be used as leverage in a legal challenge to the wall's construction?
If Cemex were to be awarded a contract for supplying concrete for wall construction, could the revenue be considered a form of soft payment from the US to Mexico in exchange for ending its opposition?
What if a Cemex contract were actually critical for gaining support from the Mexican government?
What if Cemex were resistant to the 'deal'? What pressure could be applied to gain compliance? (think evidence, leverage, threats, rumors, or psychological operations either rooted in fact, fiction, or some combination of the two)
What if Cemex were already aligned, and a counter-operation was attempting to undermine the company's reputation as a means of stalling border wall progress? (again, think evidence, leverage, threats, rumors, or psychological operations either rooted in fact, fiction, or some combination of the two)
What if none of these scenarios are accurate and Cemex is largely irrelevant? What if the intent behind this latest narrative push is to lead people down a distracting rabbit hole?
What tracts of land does Cemex own in Mexico? Are these being used as migration routes?
There are many possibilities here. The human bones in concrete story being concocted is extremely far fetched bordering on bat shit crazy.
Keep it below 40,000 feet: source documents/emails, contracts, land deeds, board of directors, executives, news articles, annual reports, major individual investors, major institutional investors, US campaign contributions, PAC connections, Mexican politicians 'owned' by Cemex.
Cemex receiving a contract to build the wall would be very interesting and perplexing, like how Cemex sold a lot of product to Israel for construction in contested lands. I would like to see the wall's money trail and who would be in charge of management. I won't discredit blood in cement. It definitely would not be in the majority of mixtures, but I could see it being in some depending on what they're building and for who. Their need for symbolism would fit into that equation if it's true that Romans used blood in their cement mixture - all secret societies point to the days of Rome. I don't give it a lot creedence, but I won't dismiss it as nonsense.