transactions – Why does Bitcoincharts have inactive CSV data dumps in the non-inactive dir?

I discovered this goldmine of Bitcoin transaction data today, and have been coding all day to download them all and insert into my local database table:

However, something confuses me about this. As you can see, there is a sub-directory literally called “inactive_exchanges”, leading me to assume that all the dead exchanges’ data is in that dir. And it does contain a bunch of old files. So far: perfectly logical.

However, I’ve discovered that a lot of the data dump files in the main dir actually are from dead exchanges. For example, the abucoinsUSD one, if downloaded and looked at, has records only between:

2017-09-21 16:03:06
2018-05-29 16:26:15

Sure, they may not have data before 2017 because they may have started that year, but 2018 is the last year where they have data, and the current year is 2020. That means it’s been dead or stale for two years now. Yet it’s not in the “inactive exchanges” dir. How can this be explained?

I was extremely happy when I finally found such a good data source, but of course there’s always some catch. In this case, it seems to be that they have a bunch of dead exchanges still in the “live” dir, which makes me worried about the quality of the data in general.

At least it seems so far like the big files, for the known exchanges, have full data. But still, I wish I could get this straightened out.

Please note: I’ve already e-mailed them about other things and they don’t respond, like 99% of all companies/people I e-mail these days. So I can’t “just ask them”.