I am not sure what would you expect.
Bull run also means increased awareness. A lot of new people will then come here.

Some will promote low quality projects and plain scams.
Some will come asking the same questions over and over again.
Some will join bounties and will spam this forum and all possible social media for some extra cents.
Some will come to troll and spread FUD.

Unfortunately many people that come here have their own agenda and learning and being useful may not be part of that.

Isn't it like that everywhere on this world? And we aren't really searching for another planet because of this

I would say the moderation is the same in that the mods are still
doing their job although there is quite a lot more users since 2017,
we just passed 3 million registered users although there aren't
3 million active members there has to be a lot more activity.

Everyone has their own agenda and not everyone wants to get involved
until they want a specific question answered like "Will Bitcoin keep going up?"

Post quality going to shit in a bull market isn't really new here. It just makes sense that as prices go up, people would be a lot more interested in grabbing some bitcoin(or crypto). All you can do right now is to do your part into make sure that these shit posts will be reported. Sometimes it just takes time for them to be removed due to the increasing number of spammers, and the limited number of mods/admins.

very representative 

That's right, and your answer is right to answer the OP's question. Here we as old users should appreciate that newcomers do not know that their topic has been previously discussed. although in the end the moderator will delete it or not even be deleted, not because the moderator just left the topic, but we as users must participate and contribute to it. For example, helping modertors and working on reports.
Isn't this our job as forum residents, to contribute to each other.
As for the OP what the OP said:


This seems selfish, because in this forum there are almost 100+ topics every day, so why not try to read and create quality topics. or is he lazy to read?

On the contrary, I noticed that the forum has improved a lot in terms of contents ever since the "Report to moderator" button was added. Now, it is either a user will improve one's posts or get tired of making post after post only to end up deleted by mods. Additionally, there is also a ban imposed on users who are found to have a pattern of making unconstructive posts.

If there is a sudden spike of worthless topics during a bull run, this is very temporary. You will notice that after mere minutes or an hour or two at most, these topics are already gone.

Yeah,every time there's a Bitcoin bull run the forum gets stuck with all the:
"Will Bitcoin price hit X USD?" "Will the Bitcoin price crash and how much?" "What will happen with Bitcoin in (insert random month or year)?" "Bitcoin is a scam,bla bla bla." " Bitcoin failed at scaling,BCH is the future..."
Seriously,do newbies have to ask all those pointless questions again and again?
The forum moderation kinda improved,especially compared with 3-4 years ago.
All those low quality topics eventually get deleted,but it takes time.

Agree to this, every time the bull-market starts topics asked are about prices, prediction, suggestion for investment, etc, which in some cases are repetitive. Which are mostly from new users looking who just came in since this forum as what you have said is the best source of information. The moderators are still active on filtering the threads with topics that are irrelevant and even posts that has no substance or help to the topic. This is correct that each users here has their own agenda, this is where people who shill and even spread FUD to their job.

It is the fear of missing out on the opportunity. Everyone in this forum own cryptocurrencies from $ 1 to 1 million. This fear is what prompts people to believe any statement and repeat a lot of discussions.
Greed is the second factor because the higher the price, that an increase in the price means the possibility of obtaining more money and thus making profits easily.

between fear and Greed the quality of posts changes. you can use userscript to ignore some spam users.

Then ignore the topics you think that doesn't seems to be useful to you and stick with the ones that are beneficial and have a sense. This forum has a moderators of course, you can also report useless  or repeated topics all you want. If you explore this forum this a button at the right side.

On the other hand, members are usually replying to those topics that are new and popped up in the first page. Whenever there is a bull run or bearish moment of bitcoin, expect unworthy topics but of course moderators are doing their job to stay this community clean and have a healthy conversations through meaningful topics.

Of course, this isn't a forum for those who are intellectual people, everyone can go here and ask even it's been asked for multiple times. That's how a platform works where discussion is non-stop even it's already been tackled many times. If you want more complex learning you could go on Coursera and study there, watch educational videos about crypto on YouTube. This platform is open for everyone even if you're dumb, don't expect that users will create complex topics just for you who already have learned a lot. Also, moderators are doing their best to retain those topics that are updated and helpful, you can simply ignore if you don't like the topics or if you want some spice, then made a topic that is extraordinary.