That may be, but it seems that Akamai CDN is still giving them a data feed. From that press release:
"As a result of the pixel-free technology partnership, MediaMath's clients will gain access to more data for audience segmentation, retargeting, and optimization, with quick and easy activation."
"As a result of the pixel-free technology partnership, MediaMath's clients will gain access to more data for audience segmentation, retargeting, and optimization, with quick and easy activation."