Assuming your blue travel document says "Convention of 28 July 1951" then no, you do not need a visa. It's important to add however, that (as you've noticed) the rules are not uniform across the Schengen area. If you plan to visit more than one Schengen country, even just passing through on your way to another Schengen country, you have to check the requirements for each country separately.
Here is an official source for Germany:
Holders of the following British travel documents (irrespective of their nationality)
- Convention Travel Documents for Refugees (1951 United Nations Convention relating to the Status of Refugees, dark blue), issued by the United Kingdom,
- Stateless Person’s Travel Documents (1954 United Nations Convention relating to the Status of Stateless Persons, red), issued by the United Kingdom,
do not require a visa for travel to Germany provided that the duration of their stay does not exceed 90 days within any 180 day period. Please note that you may not take up any employment or pursue any gainful economic activity in Germany unless such employment is explicitly authorised by a visa or a residence permit issued by the local immigration office (“Ausländerbehörde”) in Germany.
Holders of British Certificates of Travel (black)
require visas for any kind of stay.
Here's what The Netherlands has to say:
Travel document issued by a country outside Schengen? You may need a visa
Did a country outside the Schengen Area issue your travel document for refugees or stateless persons? Whether you need a visa depends on your travel document.
I have a travel document for refugees that says ‘Convention of 28 July 1951’
Does your travel document say ‘Convention of 28 July 1951’ on its cover? If so, you do not need a visa if your travel document was issued by one of the countries on the list:
- Bulgaria
- Croatia
- Cyprus
- Ireland
- Romania
- United Kingdom
You can stay in the Netherlands without a visa for a maximum of 90 days in a 180-day period. You will, however, still need to meet certain requirements.
Find out about the requirements to travel to the Netherlands without a visa
Please note that if you want to travel to other countries in the Schengen Areaduring your trip, you may need a visa for those countries. Contact the embassy of those countries to find out whether you need a visa.
Was your travel document issued by a country not on the list? If so, you do need a Schengen visa for your trip to the Netherlands.
Find out how to apply for a Schengen visa in your country
(Links in original have been removed)
By contrast, Denmark has this to say about travel documents issued under the 1951 convention:
The following aliens may enter Denmark without having their passports or
other valid travel identity documents endorsed with an entry visa in
advance:
...
Holders of valid travel documents issued in pursuance of the Convention
of 28 July 1951 relating to the Status of Refugees or the Agreement of 15
October 1946 on the introduction of Travel Documents for Refugees
A condition for the exemption from visa requirements is that the travel
document has been issued by one of the EU Member States/Schengen States and that the holder is a legal resident of the country that issued the travel
document.
...
Since the UK is no longer a member state of the European Union, you need a visa to visit Denmark with your travel document, unlike the situation in the Netherlands and Germany.