Hi Robert!

You raise a good point that there is still no experimental evidence for WIMPS. However, the problem with MACHOs is that they are composed of baryonic matter. Very strict abundance constraints were placed on this form of matter through the WMAP, COBE and PLANCK experiments. (The primary abundance constraint arguments come from the angular power spectrum and big bang nucleosynthesis.) There are indeed dark baryons out there, but even when they become accounted for, due to the aforementioned constraints, they aren’t abundant enough and won’t explain the gravitational anomalies. Yet, until evidence arises, it is difficult to conclusively rule anything out.

Thanks for the comment!