It is a non-profit organisation which clearly states that all information on the website is for public use apart from their drawings and externally submitted photographs. I do not see how this is "unclear" in terms of public usage of their data.

"All information provided on the CTBUH Tall Building Database is available for public use and inclusion within research if applicable citations referencing the Council on Tall Buildings and Urban Habitat (CTBUH) are made. Please note that while CTBUH Tall Building Database data is available for public use, images are not." 

It is clearly stated that elevation diagrams on the same building page where I source all my data, is not for public use.

"All diagrammatic elevations on building profile pages are produced and owned by CTBUH. To utilize these in a collaborative research activity with CTBUH, please contact research@ctbuh.org. For utilization in news publications, please contact press@ctbuh.org."
https://www.ctbuh.org/about/faq

Since the company clearly states that the diagrams and photos specifically are not for public use, while data, which can be found on the same page, is specifically singled out as "for public use" it is easily concluded that sourcing from their database (if citations are included, that is a fail on my part and I will correct them) is clearly acceptable.

I will update the tags add the source for each building I have changed.