As of July 2019 according to the Speedtest.net Global Index , Madagascar (unranked mobile, rank 68 fixed) ranks below all of the 3 listed countries: United Kingdom (rank 50 mobile, rank 41 fixed), France (rank 18 mobile, rank 15 fixed) and Canada (rank 6 mobile, rank 12 fixed).
Even in 2017 (August 2017 Wayback Machine data), it still ranks below all of the 3 tested countries.
Other speed test trackers such as Netflix ISP Speed Index don't track Madagascar.
Only one source put Madagascar above the other countries, that being the Cable.co.uk dataset which was summarised by Fastmetrics. In the summary, you can see that Madagascar only had ~4000 datapoints out of the 163 million speed tests, which is the likely cause of the inflated ranking. The Speedtest.net results also show a similar lack of results, with most months lacking enough data for a ranking.
It's unlikely that the average Malagasy had faster internet speeds than any of the 3 listed countries, considering the statistically insignificant number of results.