I swear some people will cling to anything to try to justify their confirmation bias.
Just because a noise was heard doesn’t mean they had confirmation that the titan had imploded.
In fact had they not searched for the submersible after hearing the noise it probably would have triggered even more problems and conspiracies. Why not search for them if you haven’t confirmed their deaths? It would be PR suicide to not search if they haven’t gotten certain confirmation.
They had to keep searching. If it was my loved ones down there I’d want someone to search for them if possible and if their death hadn’t been fully confirmed. You don’t just give up because you MIGHT have heard a sound. You get visual confirmation as long as there’s a chance that the oxygen could last that long (which that time has now expired).
No conspiracy needed. This can all be explained with good ol’ logic and reason.