Earlier quoted context omitted.
"Can we be sure you're going to stick to this trade agreement?" "Why would you think we wouldn't?" "You're breaking your treaty with the EU."
When that treaty is merely "you cannot sign trade deals" I don't think people signing trade deals would care. That rule exists for the EU's benefit, not for the benefit of member states.
The UK signed the deal knowing the consequences of it, why would another country sign a trade deal with you knowing that you will not follow the terms due to your countries internal politics ?