Iudex dicit fraudem non solum emptori, sed etiam toti civitati nocere atque turpem esse.

Because the sentence uses indirect statement after dicit (says). In Latin, indirect statement is usually built with:

• an accusative subject
• plus an infinitive

So in fraudem ... nocere atque turpem esse, fraudem is the subject of both infinitives, but in indirect statement that subject appears in the accusative.

So:

• direct idea: fraus nocet et turpis est = fraud harms and is shameful
• reported after dicit: dicit fraudem nocere atque turpem esse = he says that fraud harms and is shameful

Because nocere (to harm) takes the dative case in Latin.

So:

• emptori nocere = to harm the buyer
• civitati nocere = to harm the state/community

This is different from English, where we would use a direct object: harm the buyer.
In Latin, the person or thing affected by nocere is put in the dative.

It means not only ... but also ...

Here:

• non solum emptori = not only to the buyer
• sed etiam toti civitati = but also to the whole state

This is a very common Latin pair, and it works much like the English expression.

Toti is an adjective agreeing with civitati.

• civitati = dative singular of civitas
• toti = dative singular feminine of totus, meaning whole or entire

Since nocere takes the dative, both the noun and its adjective must be in the dative:

• toti civitati = to the whole state

Again, this is because of indirect statement after dicit.

In a main statement, you might say:

• fraus turpis est = fraud is shameful

But after dicit, Latin changes this to accusative + infinitive:

• dicit fraudem turpem esse = he says that fraud is shameful

So:

• fraudem = accusative subject
• esse = infinitive
• turpem = predicate adjective agreeing with fraudem

Because it agrees with fraudem.

• fraus is a feminine noun
• in indirect statement its subject becomes fraudem (accusative singular)
• the adjective describing it must match in gender, number, and case

So:

• fraudem = feminine singular accusative
• turpem = feminine singular accusative

Yes. Atque here links:

• nocere = to harm
• esse = to be

So the structure is:

• fraudem ... nocere
• atque turpem esse

In other words, the judge says that fraud harms ... and is shameful.

You can think of atque here as meaning and.

Yes. Fraudem is the understood subject of both infinitives.

So the sentence says that fraud:

• harms not only the buyer but also the whole state
• and is shameful

Latin often avoids repeating the accusative subject when the same word applies to more than one infinitive.

Iudex is nominative singular, and it is the subject of dicit.

So:

• iudex = the judge
• dicit = says

The overall structure is:

• Iudex dicit = The judge says
• followed by the indirect statement: fraudem ... nocere atque turpem esse

Because after verbs of saying, thinking, knowing, and similar verbs, classical Latin very often uses accusative + infinitive instead of a clause with that.

So English says:

• The judge says that fraud is shameful

But Latin commonly says:

• Iudex dicit fraudem turpem esse

This is one of the most important sentence patterns in Latin.

Latin word order is much more flexible because grammatical endings show each word’s role.

This sentence places important ideas in a natural Latin order:

• Iudex dicit first gives the main statement
• fraudem introduces the topic of the indirect statement
• non solum ... sed etiam ... keeps the paired contrast together
• nocere atque turpem esse saves the infinitives for the end

A more English-like order would be less natural in Latin. The endings, not the position alone, tell you how the sentence works.